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+= Iptables !
+Apostolos rootApostolos@swarmlab.io
+// Metadata:
+:description: iptables
+:keywords: sec, tcpdump
+:data-uri:
+:toc: right
+:toc-title: Table of Contents
+:toclevels: 4
+:source-highlighter: highlight
+:icons: font
+:sectnums: 
+
+include::header.adoc[]
+
+
+{empty} +
+
+
+
+
+
+== iptables
+
+
+**iptables** is a command line utility for configuring Linux kernel **firewall** implemented within the https://en.wikipedia.org/wiki/Netfilter[Netfilter] project. The term ''iptables'' is also commonly used to refer to this kernel-level firewall. It can be configured directly with iptables, or by using one of the many 
+
+https://en.wikipedia.org/wiki/Iptables[More: wikipedia]
+
+- Console tools 
+
+and 
+
+- Graphical  front-ends. 
+
+**iptables** is used for https://en.wikipedia.org/wiki/IPv4[IPv4] and ''ip6tables'' is used for ihttps://en.wikipedia.org/wiki/IPv6[IPv6]. Both ''iptables'' and ''ip6tables'' have the same syntax, but some options are specific to either IPv4 or IPv6.
+
+
+=== Installation
+
+The Swarmlab.io kernel is compiled with iptables support. 
+
+
+=== Front-ends
+
+==== Console
+
+- Shorewall, High-level tool for configuring Netfilter. 
+
+You describe your firewall/gateway requirements using entries in a set of configuration files.
+
+http://www.shorewall.net/[shorewall]
+
+- Arno's Secure firewall for both single and multi-homed machines. 
+
+Very easy to configure, handy to manage and highly customizable. Supports: NAT and SNAT, port forwarding, ADSL ethernet modems with both static and dynamically assigned IPs, MAC address filtering, stealth port scan detection, DMZ and DMZ-2-LAN forwarding, protection against SYN/ICMP flooding, extensive user definable logging with rate limiting to prevent log flooding, all IP protocols and VPNs such as IPsec, plugin support to add extra features.|
+
+http://rocky.eld.leidenuniv.nl/[arno-iptables-firewall]
+
+- FireHOL Language to express firewalling rules, not just a script that produces some kind of a firewall. It makes building even sophisticated firewalls easy - the way you want it.
+
+http://firehol.sourceforge.net
+
+- firewalld  (firewall-cmd) Daemon and console interface for configuring network and firewall zones as well as setting up and configuring firewall rules.
+
+https://firewalld.org[firewalld]
+
+==== Graphical
+
+- Firewall Builder 
+
+firewall configuration and management tool that supports iptables (netfilter), ipfilter, pf, ipfw, Cisco PIX (FWSM, ASA) and Cisco routers extended access lists. The program runs on Linux, FreeBSD, OpenBSD, Windows and macOS and can manage both local and remote firewalls.
+
+http://fwbuilder.sourceforge.net[fwbuilder]
+
+- firewalld 
+
+(firewall-config) Daemon and graphical interface for configuring network and firewall zones as well as setting up and configuring firewall rules.
+
+https://firewalld.org[firewalld]
+
+- FireStarter 
+
+High-level GUI Iptables firewall for Linux systems
+
+http://www.fs-security.com[firestarter]
+
+== Basic concepts
+
+iptables is used to inspect, modify, forward, redirect, and/or drop IP packets.  
+
+- The code for filtering IP packets is already built into the kernel and is organized into a collection of **tables**, each with a specific purpose.  
+- The tables are made up of a set of predefined **chains**, and the chains contain **rules** which are traversed in order. 
+- Each rule consists of a predicate of potential matches and a corresponding action (called a **target**) which is executed if the predicate is true; i.e. the conditions are matched.  
+- If the IP packet reaches the end of a built-in chain, including an empty chain, then the chain's **policy** target determines the final destination of the IP packet.  
+
+iptables is the user utility which allows you to work with these chains/rules.  
+
+
+.Understanding how iptables works
+[NOTE]
+====
+The key to understanding how iptables works is http://docs.swarmlab.io/lab/sec/tables_traverse.jpg[this chart].  
+
+The lowercase word on top is the **table** and the upper case word below is the **chain**.  
+
+- Every IP packet that comes in **on any network interface** passes through this flow chart from top to bottom.  
+
+
+**All interfaces are handled the same way; it's up to you to define rules that treat them differently.**
+
+Some packets 
+
+- are intended for local processes, hence come in from the top of the chart and stop at **Local Proces**, 
+
+- while other packets are generated by local processes; hence start at **Local Process** and proceed downward through the flowchart.  
+
+A detailed explanation http://docs.swarmlab.io/lab/sec/ex-3a_iptables-flow-chart.adoc.html[here].
+====
+
+In the vast majority of use cases you won't need to use the **raw**, **mangle**, or **security** tables at all.  
+
+Consequently, the following chart depicts a simplified network packet flow through **iptables**:
+
+[source,bash]
+----
+
+                               XXXXXXXXXXXXXXXXXX
+                             XXX     Network    XXX
+                               XXXXXXXXXXXXXXXXXX
+                                       +
+                                       |
+                                       v
+ +-------------+              +------------------+
+ |table: filter| <---+        | table: nat       |
+ |chain: INPUT |     |        | chain: PREROUTING|
+ +-----+-------+     |        +--------+---------+
+       |             |                 |
+       v             |                 v
+ [local process]     |           ****************          +--------------+
+       |             +---------+ Routing decision +------> |table: filter |
+       v                         ****************          |chain: FORWARD|
+****************                                           +------+-------+
+Routing decision                                                  |
+****************                                                  |
+       |                                                          |
+       v                        ****************                  |
++-------------+       +------>  Routing decision  <---------------+
+|table: nat   |       |         ****************
+|chain: OUTPUT|       |               +
++-----+-------+       |               |
+      |               |               v
+      v               |      +-------------------+
++--------------+      |      | table: nat        |
+|table: filter | +----+      | chain: POSTROUTING|
+|chain: OUTPUT |             +--------+----------+
++--------------+                      |
+                                      v
+                               XXXXXXXXXXXXXXXXXX
+                             XXX    Network     XXX
+                               XXXXXXXXXXXXXXXXXX
+----
+
+=== Table
+
+iptables contains five tables:
+
+.Chains 
+[NOTE]
+====
+Tables consist of **chains**, which are lists of rules which are followed in order. 
+====
+
+==== Filter
+
+This is the default table. 
+
+.Its built-in chains are:
+[source,bash]
+----
+        Input: packets going to local sockets
+        Forward: packets routed through the server
+        Output: locally generated packets
+----
+
+==== Nat 
+
+When a packet creates a new connection, this table is used. 
+
+
+.Its built-in chains are:
+[source,bash]
+----
+        Prerouting: designating packets when they come in
+        Output: locally generated packets before routing takes place
+        Postrouting: altering packets on the way out
+----
+
+==== Mangle 
+
+Used for special altering of packets.
+
+.Its built-in chains are:
+[source,bash]
+----
+        Prerouting: incoming packets
+        Postrouting: outgoing packets
+        Output: locally generated packets that are being altered
+        Input: packets coming directly into the server
+        Forward: packets being routed through the server
+----
+
+==== Raw 
+
+Primarily used for configuring exemptions from connection tracking.
+
+.Its built-in chains are:
+[source,bash]
+----
+        Prerouting: packets that arrive by the network interface
+        Output: processes that are locally generated
+----
+
+==== Security 
+
+Used for Mandatory Access Control (MAC) rules. After the filter table, the security table is accessed next. 
+
+.Its built-in chains are:
+[source,bash]
+----
+        Input: packets entering the server
+        Output: locally generated packets
+        Forward: packets passing through the server
+----
+
+
+
+[NOTE]
+====
+In most common use cases you will only use two of these: **filter** and **nat**.  
+====
+
+
+=== Rules 
+
+Packet filtering is based on **rules**, which are specified by multiple **matches** (conditions the packet must satisfy so that the rule can be applied), and one **target** (action taken when the packet matches all conditions).  
+
+The typical things a rule might match on are 
+
+- what interface the packet came in on (e.g eth0 or eth1), 
+- what type of packet it is (ICMP, TCP, or UDP), 
+- or the destination port of the packet.
+
+Targets are specified using the **-j** or **--jump** option. 
+
+Targets can be either 
+- user-defined chains (i.e. if these conditions are matched, jump to the following user-defined chain and continue processing there), one of the special built-in targets, 
+- or a target extension. 
+
+[NOTE]
+====
+- Built-in targets are **ACCEPT**, **DROP**, **QUEUE** and **RETURN** 
+- target extensions are, for example, **REJECT** and **LOG**. 
+====
+
+- If the target is a built-in target, the fate of the packet is decided immediately and processing of the packet in current table is stopped. 
+
+- If the target is a user-defined chain and the fate of the packet is not decided by this second chain, it will be filtered against the remaining rules of the original chain. 
+
+Target extensions can be either **terminating** (as built-in targets) or **non-terminating** (as user-defined chains) 
+
+=== Traversing Chains 
+
+A network packet received on any interface traverses the traffic control chains of tables in the order shown in the http://docs.swarmlab.io/lab/sec/tables_traverse.jpg[this chart]
+
+- The first routing decision involves deciding if the final destination of the packet is the local machine (in which case the packet traverses through the **INPUT chains** 
+
+- or elsewhere (in which case the packet traverses through the **FORWARD chains**.  
+
+- Subsequent routing decisions involve deciding what interface to assign to an outgoing packet.  
+
+At each chain in the path, every rule in that chain is evaluated in order and whenever a rule matches, the corresponding target/jump action is executed.  
+
+The 3 most commonly used targets are **ACCEPT**, **DROP**, and **jump** to a user-defined chain.  
+
+[NOTE]
+====
+While built-in chains can have default policies, user-defined chains can not.  
+====
+
+- If every rule in a chain that you jumped fails to provide a complete match, the packet is dropped back into the calling chain as illustrated 
+http://docs.swarmlab.io/lab/sec/images/table_subtraverse.jpg[here].  
+
+- If at any time a complete match is achieved for a rule with a **DROP** target, the packet is dropped and no further processing is done.  
+- If a packet is **ACCEPT**ed within a chain, it will be **ACCEPT**ed in all superset chains also and it will not traverse any of the superset chains any further.  
+
+However, be aware that the packet will continue to traverse all other chains in other tables in the normal fashion.
+
+
+
+== Usage
+
+=== Showing the current rules
+
+[source,bash]
+----
+# iptables -nvL
+
+Chain INPUT (policy ACCEPT 0 packets, 0 bytes)
+ pkts bytes target     prot opt in     out     source               destination
+
+Chain FORWARD (policy ACCEPT 0 packets, 0 bytes)
+ pkts bytes target     prot opt in     out     source               destination
+
+Chain OUTPUT (policy ACCEPT 0 packets, 0 bytes)
+ pkts bytes target     prot opt in     out     source               destination
+----
+
+If the output looks like the above, then there are no rules (i.e. nothing is blocked) in the default filter table
+
+
+=== Resetting rules
+
+You can flush and reset iptables to default using these commands:
+
+[source,bash]
+----
+# iptables -F
+# iptables -X
+# iptables -t nat -F
+# iptables -t nat -X
+# iptables -t mangle -F
+# iptables -t mangle -X
+# iptables -t raw -F
+# iptables -t raw -X
+# iptables -t security -F
+# iptables -t security -X
+# iptables -P INPUT ACCEPT
+# iptables -P FORWARD ACCEPT
+# iptables -P OUTPUT ACCEPT
+----
+
+The -F command with no arguments flushes all the chains in its current table. Similarly, -X deletes all empty non-default chains in a table.
+
+Individual chains may be flushed or deleted by following -F and -X with a [chain] argument.
+
+=== Editing rules
+
+Rules can be edited by 
+
+- appending -A a rule to a chain, 
+
+- inserting -I it at a specific position on the chain, 
+
+- replacing -R an existing rule, 
+
+- or deleting -D it. 
+
+The first three commands are exemplified in the following.
+
+First of all, our computer is not a router (unless, of course, it is a router). We want to change the default policy on the FORWARD chain from ACCEPT to DROP.
+
+[source,bash]
+----
+# iptables -P FORWARD DROP
+----
+
+
+
+=== Examples
+
+[NOTE]
+====
+We are going to use Shorewall as an iptables configuration tool. 
+
+See Appendix.
+====
+
+Here are some examples of "raw" iptables command lines.
+
+
+==== Block Traffic by PortPermalink
+
+You may use a port to block all traffic coming in on a specific interface. 
+
+For example:
+
+[source,bash]
+----
+iptables -A INPUT -j DROP -p tcp --destination-port 110 -i eth0
+----
+
+Let’s examine what each part of this command does:
+
+- **-A** will add or append the rule to the end of the chain.
+
+    **INPUT** will add the rule to the table.
+
+    **DROP** means the packets are discarded.
+
+- **-p tcp** means the rule will only drop TCP packets.
+
+- **--destination-port 110** filters packets targeted to port 110.
+
+- **-i eth0** means this rule will impact only packets arriving on the eth0 interface.
+
+
+==== Drop Traffic
+
+In order to drop all incoming traffic from a specific IP address, use the iptables command with the following options:
+
+[source,bash]
+----
+iptables -I INPUT -s 198.51.100.0 -j DROP
+----
+
+To remove these rules, use the **--delete** or **-D** option:
+
+[source,bash]
+----
+iptables --delete INPUT -s 198.51.100.0 -j DROP
+iptables -D INPUT -s 198.51.100.0 -j DROP
+----
+
+
+==== Block or Allow Traffic by Port Number 
+
+One way to create a firewall is to block all traffic to the system and then allow traffic on certain ports. 
+
+Below is a sample sequence of commands to illustrate the process:
+
+[source,bash]
+----
+iptables -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
+iptables -A INPUT -i lo -m comment --comment "Allow loopback connections" -j ACCEPT
+iptables -A INPUT -p icmp -m comment --comment "Allow Ping to work as expected" -j ACCEPT
+iptables -A INPUT -p tcp -m multiport --destination-ports 22,25,53,80,443,465,5222,5269,5280,8999:9003 -j ACCEPT
+iptables -A INPUT -p udp -m multiport --destination-ports 53 -j ACCEPT
+iptables -P INPUT DROP
+iptables -P FORWARD DROP
+----
+
+Let’s break down the example above. 
+
+The **first two** commands add or append rules to the **INPUT chain** in order to allow access on specific ports. 
+
+The **-p tcp** and **-p udp** options specify either **UDP** or **TCP** packet types. 
+
+The **-m** multiport function matches packets on the basis of their source or destination ports, and can accept the specification of up to 15 ports. 
+
+Multiport also accepts **ranges such as 8999:9003** which counts as 2 of the 15 possible ports, but matches ports 8999, 9000, 9001, 9002, and 9003. 
+
+The next command **allows all incoming** and **outgoing packets** that are associated with existing connections so that they will not be inadvertently blocked by the firewall. 
+
+The final two commands use the **-P** option to describe the **default policy** for these chains. As a result, all packets processed by **INPUT** and **FORWARD** will be dropped by default.
+
+[NOTE]
+====
+Note that the rules described above only control incoming packets, and do not limit outgoing connections.
+====
+
+=== More Examples
+
+[source,bash]
+----
+# Allow all loopback (lo0) traffic and reject traffic
+# to localhost that does not originate from lo0.
+-A INPUT -i lo -j ACCEPT
+-A INPUT ! -i lo -s 127.0.0.0/8 -j REJECT
+
+# Allow ping.
+-A INPUT -p icmp -m state --state NEW --icmp-type 8 -j ACCEPT
+
+# Allow SSH connections.
+-A INPUT -p tcp --dport 22 -m state --state NEW -j ACCEPT
+
+# Allow HTTP and HTTPS connections from anywhere
+# (the normal ports for web servers).
+-A INPUT -p tcp --dport 80 -m state --state NEW -j ACCEPT
+-A INPUT -p tcp --dport 443 -m state --state NEW -j ACCEPT
+
+# Allow inbound traffic from established connections.
+# This includes ICMP error returns.
+-A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
+
+# Log what was incoming but denied (optional but useful).
+-A INPUT -m limit --limit 5/min -j LOG --log-prefix "iptables_INPUT_denied: " --log-level 7
+
+# Reject all other inbound.
+-A INPUT -j REJECT
+
+# Log any traffic that was sent to you
+# for forwarding (optional but useful).
+-A FORWARD -m limit --limit 5/min -j LOG --log-prefix "iptables_FORWARD_denied: " --log-level 7
+
+# Reject all traffic forwarding.
+-A FORWARD -j REJECT
+----
+
+
+[appendix]
+== How to use iptables
+
+
+
+Shorewall is not the easiest to use of the available iptables configuration tools but I believe that it is the most flexible and powerful. 
+
+It can handle complex and fast changing network environments. 
+
+It needs multiple configuration files, even for simple setups. 
+
+Suitable for powerusers! - Most likely there are a lot of these among our Students :-) 
+
+Shorewall is very popular!
+
+
+
+
+
+https://wiki.archlinux.org[Origin]
+
+
+
+
+
+
+:hardbreaks:
+
+{empty} +
+{empty} +
+{empty} 
+
+:!hardbreaks:
+
+'''
+
diff --git a/labs/os2/LICENSE b/labs/os2/LICENSE
new file mode 100644
index 0000000..82b5650
--- /dev/null
+++ b/labs/os2/LICENSE
@@ -0,0 +1,614 @@
+GNU AFFERO GENERAL PUBLIC LICENSE
+
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diff --git a/labs/os2/README.md b/labs/os2/README.md
new file mode 100644
index 0000000..15dc6b3
--- /dev/null
+++ b/labs/os2/README.md
@@ -0,0 +1,3 @@
+# sec
+
+Σκοπός του εργαστηρίου είναι η εμβάθυνση των θεωρητικών και πρακτικών γνώσεων που ήδη έχει ο φοιτητής σε δίκτυα υπολογιστών και στην περιοχή της ασφάλειας υπολογιστών, ώστε να καλύψει το πλαίσιο γνώσεων της επιστημονικής περιοχής “Ασφάλειας Δικτύων και Επικοινωνιών”.
diff --git a/labs/os2/basics.png b/labs/os2/basics.png
new file mode 100644
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diff --git a/labs/os2/dmz1.png b/labs/os2/dmz1.png
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diff --git a/labs/os2/ex-3a_iptables-flow-chart.adoc b/labs/os2/ex-3a_iptables-flow-chart.adoc
new file mode 100644
index 0000000..276275a
--- /dev/null
+++ b/labs/os2/ex-3a_iptables-flow-chart.adoc
@@ -0,0 +1,104 @@
+= Iptables - Traversing of tables and chains!
+Apostolos rootApostolos@swarmlab.io
+// Metadata:
+:description: Intro and Install
+:keywords: sec, tcpdump
+:data-uri:
+:toc: right
+:toc-title: Table of Contents
+:toclevels: 4
+:source-highlighter: highlight
+:icons: font
+:sectnums: 
+
+
+
+{empty} +
+
+
+
+== General
+
+When a packet first enters the firewall, it hits the hardware and then gets passed on to the proper device driver in the kernel. 
+
+Then the packet starts to go through a series of steps in the kernel, before it is either sent to the correct application (locally), or forwarded to another host - or whatever happens to it. 
+
+
+== Destination local host (our own machine)
+
+.Destination local host
+|===
+|Step|	Table|	Chain|	Comment
+|1| | |	 	 	On the wire (e.g., Internet)
+|2| | |	 	 	Comes in on the interface (e.g., eth0)
+|3|	raw|	PREROUTING|	This chain is used to handle packets before the connection tracking takes place. It can be used to set a specific connection not to be handled by the connection tracking code for example.
+|4| | |	 	 	This is when the connection tracking code takes place
+|5|	mangle|	PREROUTING|	This chain is normally used for mangling packets, i.e., changing TOS and so on.
+|6|	nat|	PREROUTING|	This chain is used for DNAT mainly. Avoid filtering in this chain since it will be bypassed in certain cases.
+|7| | |	 	 	Routing decision, i.e., is the packet destined for our local host or to be forwarded and where.
+|8|	mangle|	INPUT|	At this point, the mangle INPUT chain is hit. We use this chain to mangle packets, after they have been routed, but before they are actually sent to the process on the machine.
+|9|	filter|	INPUT|	This is where we do filtering for all incoming traffic destined for our local host. Note that all incoming packets destined for this host pass through this chain, no matter what interface or in which direction they came from.
+|10| | |	 	 	Local process or application (i.e., server or client program). 
+|===
+
+
+== Source local host (our own machine)
+
+.Source local host 
+|===
+|Step|	Table|	Chain|	Comment
+|1| | |	 	 	Local process/application (i.e., server/client program)
+|2| | |	 	 	Routing decision. What source address to use, what outgoing interface to use, and other necessary information that needs to be gathered.
+|3|	raw|	OUTPUT|	This is where you do work before the connection tracking has taken place for locally generated packets. You can mark connections so that they will not be tracked for example.
+|4| | |	 	 	This is where the connection tracking takes place for locally generated packets, for example state changes et cetera. 
+|5|	mangle|	OUTPUT|	This is where we mangle packets, it is suggested that you do not filter in this chain since it can have side effects.
+|6|	nat|	OUTPUT|	This chain can be used to NAT outgoing packets from the firewall itself.
+|7| | |  	 	Routing decision, since the previous mangle and nat changes may have changed how the packet should be routed.
+|8| 	filter|	OUTPUT|	This is where we filter packets going out from the local host.
+|9|	mangle|	POSTROUTING|	The POSTROUTING chain in the mangle table is mainly used when we want to do mangling on packets before they leave our host, but after the actual routing decisions. This chain will be hit by both packets just traversing the firewall, as well as packets created by the firewall itself.
+|10|	nat|	POSTROUTING|	This is where we do SNAT as described earlier. It is suggested that you don't do filtering here since it can have side effects, and certain packets might slip through even though you set a default policy of DROP.
+|11| | |	 	 	Goes out on some interface (e.g., eth0)
+|12| | |	 	 	On the wire (e.g., Internet)
+|===
+
+
+
+== Forwarded packets
+
+In this example, we're assuming that the packet is destined for another host on another network. The packet goes through the different steps in the following fashion: 
+
+.Forwarded packets
+|===
+|Step|	Table|	Chain|	Comment
+|1| | | 	 	 	On the wire (i.e., Internet)
+|2| | |	 	 	Comes in on the interface (i.e., eth0)
+|3|	raw|	PREROUTING|	Here you can set a connection to not be handled by the connection tracking system.
+|4| | |	 	 	This is where the non-locally generated connection tracking takes place. 
+|5|	mangle|	PREROUTING|	This chain is normally used for mangling packets, i.e., changing TOS and so on.
+|6|	nat|	PREROUTING|	This chain is used for DNAT mainly. SNAT is done further on. Avoid filtering in this chain since it will be bypassed in certain cases.
+|7| | |  	 	Routing decision, i.e., is the packet destined for our local host or to be forwarded and where.
+|8|	mangle|	FORWARD|	The packet is then sent on to the FORWARD chain of the mangle table. This can be used for very specific needs, where we want to mangle the packets after the initial routing decision, but before the last routing decision made just before the packet is sent out.
+|9|	filter|	FORWARD|	The packet gets routed onto the FORWARD chain. Only forwarded packets go through here, and here we do all the filtering. Note that all traffic that's forwarded goes through here (not only in one direction), so you need to think about it when writing your rule-set.
+|10|	mangle|	POSTROUTING|	This chain is used for specific types of packet mangling that we wish to take place after all kinds of routing decisions have been done, but still on this machine.
+|11|	nat|	POSTROUTING|	This chain should first and foremost be used for SNAT. Avoid doing filtering here, since certain packets might pass this chain without ever hitting it. This is also where Masquerading is done.
+|12| | | 	 	 	Goes out on the outgoing interface (i.e., eth1).
+|13| | |	 	 	Out on the wire again (i.e., LAN).
+|===
+
+
+
+
+
+
+
+
+
+:hardbreaks:
+
+{empty} +
+{empty} +
+{empty} 
+
+:!hardbreaks:
+
+'''
diff --git a/labs/os2/ex-4_iptables.adoc b/labs/os2/ex-4_iptables.adoc
new file mode 100644
index 0000000..8c2eaa3
--- /dev/null
+++ b/labs/os2/ex-4_iptables.adoc
@@ -0,0 +1,311 @@
+= Iptables with shorewall!
+Apostolos rootApostolos@swarmlab.io
+// Metadata:
+:description: Intro and Install
+:keywords: sec, tcpdump
+:data-uri:
+:toc: right
+:toc-title: Table of Contents
+:toclevels: 4
+:source-highlighter: highlight
+:icons: font
+:sectnums: 
+
+
+
+{empty} +
+
+
+[[cheat-Docker]]
+== Install swarmlab-sec (Home PC)
+
+HowTo: See http://docs.swarmlab.io/lab/sec/sec.adoc.html
+
+
+.NOTE
+[NOTE]
+====
+Assuming you're already logged in
+====
+
+
+
+== shorewall
+
+
+**Shorewall** is an open source firewall tool for Linux that builds upon the Netfilter (iptables/ipchains) system built into the Linux kernel, making it easier to manage more complex configuration schemes by providing a higher level of abstraction for describing rules using text files. 
+
+https://en.wikipedia.org/wiki/Shorewall[More: wikipedia]
+
+
+.NOTE
+[NOTE]
+====
+Our docker instances have only one nic
+
+to add more nic's:
+
+.create netowrk frist
+[source,bash]
+----
+docker network create --driver=bridge --subnet=192.168.0.0/16 net1
+docker network create --driver=bridge --subnet=192.168.0.0/16 net2
+docker network create --driver=bridge --subnet=192.168.0.0/16 net3
+----
+
+then connect network to container
+
+.connect network created to container
+[source,bash]
+----
+docker network connect net1 master
+docker network connect net1 worker1
+docker network connect net2 master
+docker network connect net2 worker2
+----
+
+now let's look at the following image
+
+
+====
+
+
+=== Installation
+
+Shorewall is already installed on swarmlab-sec. 
+
+
+== Basic Two-Interface Firewall
+
+
+image::basics.png[Basic Two-Interface Firewall]
+
+
+
+.connect to master first
+[NOTE]
+====
+
+Assuming you're already logged in master!
+
+master is now our Firewall/Router
+
+swarmlab-sec login 
+====
+
+
+== Shorewall Concepts
+
+The configuration files for Shorewall are contained in the directory /etc/shorewall 
+
+=== zones — Shorewall zone declaration file
+
+The /etc/shorewall/zones file declares your network zones. You specify the hosts in each zone through entries in /etc/shorewall/interfaces 
+
+
+./etc/shorewall/zones
+[source,bash]
+----
+#ZONE   TYPE     OPTIONS                 IN_OPTIONS              OUT_OPTIONS
+fw      firewall
+net     ipv4
+loc     ipv4
+----
+
+=== interfaces — Shorewall interfaces file
+
+The interfaces file serves to define the firewall's network interfaces to Shorewall. 
+
+./etc/shorewall/interfaces
+[source,bash]
+----
+#ZONE       INTERFACE       BROADCAST      OPTIONS
+net         eth0                           dhcp,routefilter
+loc         eth1            detect
+----
+
+
+=== policy — Shorewall policy file
+
+This file defines the high-level policy for connections between zone
+
+
+./etc/shorewall/policy
+[source,bash]
+----
+#SOURCE    DEST        POLICY      LOGLEVEL    LIMIT
+loc        net         ACCEPT
+net        all         DROP        info
+all        all         REJECT      info
+----
+
+
+=== rules — Shorewall rules file
+
+Entries in this file govern connection establishment by defining exceptions to the policies
+
+
+./etc/shorewall/rules
+[source,bash]
+----
+#ACTION    SOURCE    DEST               PROTO     DPORT
+ACCEPT     $FW       net                udp       53
+ACCEPT     net       $FW         	udp       53
+ACCEPT     $FW       net                tcp       80
+ACCEPT     net       $FW         	tcp       80
+----
+
+
+=== Compile then Execute
+
+Shorewall uses a "compile" then "execute" approach. The Shorewall configuration compiler reads the configuration files and generates a shell script. Errors in the compilation step cause the script to be discarded and the command to be aborted. If the compilation step doesn't find any errors then the shell script is executed.
+
+
+
+./sbin/shorewall
+[source,bash]
+----
+/sbin/shorewall start
+/sbin/shorewall stop
+/sbin/shorewall clear
+----
+
+
+
+.NOTE
+[NOTE]
+====
+The 'compiled' scripts are placed by default in the directory /var/lib/shorewall and are named to correspond to the command being executed. For example, the command /sbin/shorewall start will generate a script named /var/lib/shorewall/.start and, if the compilation is error free, that script will then be executed. If the script executes successfully, it then copies itself to /var/lib/shorewall/firewall. When an /sbin/shorewall stop or /sbin/shorewall clear command is subsequently executed, /var/lib/shorewall/firewall is run to perform the requested operation.
+
+The AUTOMAKE option in /etc/shorewall/shorewall.conf may be set to automatically generate a new script when one of the configuration files is changed. When no file has changed since the last compilation, the /sbin/shorewall start, /sbin/shorewall reload and /sbin/shorewall restart commands will simply execute the current /var/lib/shorewall/firewall script.
+====
+
+
+
+== Three-Interface Firewall
+
+
+image::dmz1.png[Three-Interface Firewall]
+
+=== zones 
+
+./etc/shorewall/zones
+[source,bash]
+----
+#ZONE   TYPE   OPTIONS                 IN_OPTIONS              OUT_OPTIONS
+fw      firewall
+net     ipv4
+loc     ipv4
+dmz     ipv4				#new line
+----
+
+=== interfaces
+
+./etc/shorewall/interfaces
+[source,bash]
+----
+#ZONE       INTERFACE       BROADCAST      OPTIONS
+net         eth0                           dhcp,routefilter
+loc         eth1            detect
+dmz         eth2            detect		#new line
+----
+
+
+=== policy 
+
+./etc/shorewall/policy
+[source,bash]
+----
+#SOURCE    DEST        POLICY      LOGLEVEL    LIMIT
+loc        net         ACCEPT
+dmz        net         DROP                    #new line
+net        all         DROP        info
+all        all         REJECT      info
+----
+
+
+=== rules
+
+./etc/shorewall/rules
+[source,bash]
+----
+#ACTION    SOURCE    DEST               PROTO     DPORT
+ACCEPT     $FW       net                udp       53
+ACCEPT     net       $FW         	udp       53
+ACCEPT     $FW       net                tcp       80
+ACCEPT     net       $FW         	tcp       80
+#New lines
+ACCEPT     $FW       dmz                udp       53
+ACCEPT     dmz       $FW         	udp       53
+ACCEPT     $FW       dmz                tcp       80
+ACCEPT     dmz       $FW         	tcp       80
+
+ACCEPT     loc       dmz                tcp       80 # Add your rules for the zones  you have defined.
+ACCEPT     dmz       loc         	tcp       80 #
+ACCEPT     loc       net                tcp       80 # This here is an example
+ACCEPT     net       loc         	tcp       80 # for communication 
+ACCEPT     dmz       net                tcp       80 # over port 80
+ACCEPT     net       dmz         	tcp       80 # aka the web
+----
+
+
+
+=== masq - Shorewall Masquerade/SNAT definition file
+
+/etc/shorewall/masq - directs the firewall where to use many-to-one (dynamic) Network Address Translation (a.k.a. Masquerading) and Source Network Address Translation (SNAT).
+
+
+./etc/shorewall/masq
+[source,bash]
+----
+#INTERFACE   SOURCE           ADDRESS         PROTO   DPORT
+eth0         eth1
+eth0         eth2
+----
+
+=== snat — Shorewall SNAT/Masquerade definition file
+
+This file is used to define dynamic NAT (Masquerading) and to define Source NAT (SNAT). It superseded shorewall-masq(5) in Shorewall 5.0.14.
+
+
+./etc/shorewall/masq
+[source,bash]
+----
+#ACTION    SOURCE              DEST
+MASQUERADE 192.168.0.0/24      eth0
+MASQUERADE 192.168.1.0/24      eth0
+----
+
+- You have a simple masquerading setup where eth0 connects to internet and eth1 connects to your local network with subnet 192.168.0.0/24.
+- You add a router to your local network to connect subnet 192.168.1.0/24 which you also want to masquerade. You then add a second entry for eth0 to this file
+
+
+[NOTE]
+====
+Beginning with that release, the Shorewall compiler will automatically convert existing masq files to the equivalent snat file, and rename the masq file to masq.bak.
+====
+
+
+=== Compile and Execute
+
+
+./sbin/shorewall
+[source,bash]
+----
+/sbin/shorewall start
+/sbin/shorewall stop
+/sbin/shorewall clear
+----
+
+
+
+:hardbreaks:
+
+{empty} +
+{empty} +
+{empty} 
+
+:!hardbreaks:
+
+'''
+
diff --git a/labs/os2/ex-5_iptables.adoc b/labs/os2/ex-5_iptables.adoc
new file mode 100644
index 0000000..9723014
--- /dev/null
+++ b/labs/os2/ex-5_iptables.adoc
@@ -0,0 +1,277 @@
+= VPN!
+Apostolos rootApostolos@swarmlab.io
+// Metadata:
+:description: Intro and Install
+:keywords: sec, tcpdump
+:data-uri:
+:toc: right
+:toc-title: Πίνακας περιεχομένων
+:toclevels: 4
+:source-highlighter: highlight
+:icons: font
+:sectnums: 
+
+include::header.adoc[]
+
+
+{empty} +
+
+
+[[cheat-Docker]]
+== Install swarmlab-sec (Home PC)
+
+HowTo: See http://docs.swarmlab.io/lab/sec/sec.adoc.html
+
+
+.NOTE
+[NOTE]
+====
+Assuming you're already logged in
+====
+
+
+
+== VPN
+
+A ***virtual private network (VPN)*** extends a private network across a public network, and enables users to send and receive data across shared or public networks as if their computing devices were directly connected to the private network. Applications running on a computing device, e.g., a laptop, desktop, smartphone, across a VPN may therefore benefit from the functionality, security, and management of the private network. Encryption is a common, though not an inherent, part of a VPN connection
+
+https://en.wikipedia.org/wiki/Virtual_private_network[More: wikipedia]
+
+image::495px-VPN_overview-en.svg.png[VPN connectivity overview]
+
+.NOTE
+[NOTE]
+====
+**OpenVPN** is an open-source software that implements virtual private network (VPN) techniques to create secure point-to-point or site-to-site connections in routed or bridged configurations and remote access facilities. It uses a custom security protocol that utilizes SSL/TLS for key exchange. It is capable of traversing network address translators (NATs) and firewalls. It was written by James Yonan and is published under the GNU General Public License (GPL).
+
+https://en.wikipedia.org/wiki/OpenVPN[More: wikipedia]
+====
+
+
+== Create VPN
+
+
+.create-vpn.sh
+[source,bash]
+----
+#!/bin/bash
+IP=192.168.89.5                                         # Server IP
+P=1194                                                  # Server Port
+OVPN_SERVER='10.80.0.0/16'                              # VPN Network
+vpn_data=/var/lib/swarmlab/openvpn/openvpn-services/    # Dir to save data ** this must exist **
+NAME=swarmlab-vpn-services                              # name of docker service
+DOCKERnetwork=swarmlab-vpn-services-network             # docker network
+docker=registry.vlabs.uniwa.gr:5080/myownvpn            # docker image
+
+docker stop  $NAME					#stop container 
+sleep 3
+docker container rm  $NAME				#rm container
+
+# rm config files
+sudo rm -f $vpn_data/openvpn.conf.*.bak
+sudo rm -f $vpn_data/openvpn.conf
+sudo rm -f $vpn_data/ovpn_env.sh.*.bak
+sudo rm -f $vpn_data/ovpn_env.sh
+
+# create network
+sleep 2
+docker network create --attachable=true --driver=bridge --subnet=172.50.0.0/16 --gateway=172.50.0.1 $DOCKERnetwork
+
+read -d '' MULTILINE_EXTRA_SERVER_CONF << EOF
+duplicate-cn
+max-clients 35000
+topology subnet
+EOF
+
+#run container
+sleep 3
+docker run --net=none -it -v $vpn_data:/etc/openvpn  --rm $docker ovpn_genconfig  -u udp://$IP:1194 \
+-N -d -c -p "route 172.50.20.0 255.255.255.0" -e "topology subnet" -s $OVPN_SERVER
+
+
+# create pki
+sleep 3
+echo "new pki is disabled"
+docker run --net=none -v $vpn_data:/etc/openvpn  --rm -it $docker ovpn_initpki
+
+#sleep 3
+#docker run --net=none -v $vpn_data:/etc/openvpn  --rm $docker ovpn_copy_server_files
+
+#create vpn
+sleep 3
+docker run --detach --name $NAME -v $vpn_data:/etc/openvpn --net=$DOCKERnetwork --ip=172.50.0.2 -p $P:1194/udp --cap-add=NET_ADMIN $docker
+
+sleep 5
+sudo sysctl -w net.ipv4.ip_forward=1
+
+#show created
+docker ps
+----
+
+
+== Create user
+
+.config
+[source,bash]
+----
+#!/bin/bash
+IP=83.212.114.14
+P=5194
+vpn_data=/var/lib/swarmlab/openvpn/openvpn-services/
+NAME=swarmlab-vpn-services
+DOCKERnetwork=swarmlab-vpn-services-network
+docker=registry.vlabs.uniwa.gr:5080/myownvpn
+PATHNAME=/var/lib/swarmlab/openvpn/etc/vpn-data_user_config
+vpn_data_user_config=$PATHNAME
+
+vpn_data=/var/lib/swarmlab/openvpn/openvpn-services/
+vpn_data_user_config=/var/lib/swarmlab/openvpn/etc/vpn-data_user_config
+NAME=swarmlab-vpn-services
+
+MANAGER=/var/lib/swarmlab/openvpn/etc/managers
+WORKER=/var/lib/swarmlab/openvpn/etc/workers
+MANAGERkeys=/var/lib/swarmlab/openvpn/etc/managers_keys
+
+----
+
+
+
+.create-user.sh
+[source,bash]
+----
+#!/bin/bash
+
+. ./config
+
+sudo mkdir -p $vpn_data
+sudo mkdir -p $vpn_data_user_config
+sudo mkdir -p $MANAGERkeys
+
+docker=registry.vlabs.uniwa.gr:5080/myownvpn
+echo $vpnip
+echo $#
+
+docker=registry.vlabs.uniwa.gr:5080/myownvpn
+echo $vpnip
+echo $#
+
+if [ $# -eq 1  ]; then
+        CLIENTNAME=$1
+        U=$CLIENTNAME
+        mkdir users
+        docker run -v $vpn_data:/etc/openvpn --rm -it $docker easyrsa build-client-full $CLIENTNAME nopass
+        sleep 3
+        docker run -v $vpn_data:/etc/openvpn --log-driver=none --rm $docker ovpn_getclient $CLIENTNAME  > users/$CLIENTNAME.ovpn
+
+        file="users/$CLIENTNAME.ovpn"
+
+        ps='remote '
+        pi="remote $IP $P udp"
+        grep -q "^$ps" $file && sed -i "s/^$ps.*/$pi/" $file || sed -i "5a $pi" $file
+
+        ps='comp-lzo'
+        pi='comp-lzo no'
+        grep -q "^$ps" $file && sed -i "s/^$ps.*/$pi/" $file || sed -i "6a $pi" $file
+
+        ps='resolv-retry'
+        pi='resolv-retry infinite'
+        grep -q "^$ps" $file && sed -i "s/^$ps.*/$pi/" $file || sed -i "7a $pi" $file
+        ps='persist-key'
+        pi='persist-key'
+        grep -q "^$ps" $file && sed -i "s/^$ps.*/$pi/" $file || sed -i "8a $pi" $file
+
+        ps='persist-tun'
+        pi='persist-tun'
+        grep -q "^$ps" $file && sed -i "s/^$ps.*/$pi/" $file || sed -i "9a $pi" $file
+
+        ps='keepalive'
+        pi='keepalive 15 60'
+        grep -q "^$ps" $file && sed -i "s/^$ps.*/$pi/" $file || sed -i "10a $pi" $file
+
+
+
+else
+        echo "no clientname"
+fi
+----
+
+
+== rm vpn user
+
+.rm-user.sh
+[source,bash]
+----
+#!/bin/bash
+. ./config
+
+CLIENTNAME=$1
+U=$CLIENTNAME
+
+if [ $# -eq 1  ]; then
+        sudo rm -f $vpn_data/pki/reqs/$CLIENTNAME.req
+        sudo rm -f $vpn_data/pki/private/$CLIENTNAME.key
+        sudo rm -f $vpn_data/pki/issued/$CLIENTNAME.crt
+        sudo rm -f $vpn_data/server/ccd/$CLIENTNAME
+        sudo rm -f $vpn_data/ccd/$CLIENTNAME
+        pem=$(sudo grep "CN=$U$"  $vpn_data/pki/index.txt | cut  -f4)
+        #/var/lab/gswarm/vpn-data/pki/certs_by_serial/BACA61827E65D0E5F695245519410952.pem
+        sudo rm -f $vpn_data/pki/certs_by_serial/$pem.pem
+        sudo sed -i "/CN=$U$/d"  $vpn_data/pki/index.txt
+        echo $pem
+        docker run -v $vpn_data:/etc/openvpn --log-driver=none --rm -it $docker ovpn_revokeclient  $CLIENTNAME remove
+
+
+        sudo rm -f $vpn_data_user_config/$CLIENTNAME.ovpn
+        sudo rm -f $vpn_data_user_config1/$CLIENTNAME.ovpn
+else
+        echo "no client"
+fi
+
+----
+
+== show all vpn users
+
+.show-user.sh
+[source,bash]
+----
+. ./config
+
+docker exec -it  $NAME ovpn_listclients
+----
+
+== show all connected vpn users
+
+.show-conn-user.sh
+[source,bash]
+----
+. ./config
+
+docker exec -it  $NAME  cat /tmp/openvpn-status.log
+----
+
+
+
+
+
+:hardbreaks:
+
+{empty} +
+{empty} +
+{empty} 
+
+:!hardbreaks:
+
+'''
+
+.Reminder
+[NOTE]
+====
+:hardbreaks:
+Caminante, no hay camino, 
+se hace camino al andar.
+
+Wanderer, there is no path, 
+the path is made by walking.
+
+*Antonio Machado* Campos de Castilla
+====
diff --git a/labs/os2/header.adoc b/labs/os2/header.adoc
new file mode 100644
index 0000000..6caffd1
--- /dev/null
+++ b/labs/os2/header.adoc
@@ -0,0 +1,5 @@
+[options="header"]
+|=======================
+|http://docs.swarmlab.io[Home] icon:home[link="http://docs.swarmlab.io", window="_self"]|http://docs.swarmlab.io/Howtos[HowTos] icon:wpbeginner[link="http://docs.swarmlab.io/Howtos", window="_self"]|http://docs.swarmlab.io/lab[Labs] icon:mixcloud[link="http://docs.swarmlab.io/lab", window="_self"]
+|=======================
+[.right.text-center]
diff --git a/labs/os2/index.adoc b/labs/os2/index.adoc
new file mode 100644
index 0000000..d02b098
--- /dev/null
+++ b/labs/os2/index.adoc
@@ -0,0 +1,40 @@
+= Practical Exercises!
+Apostolos rootApostolos@swarmlab.io
+// Metadata:
+:description: Intro and Install
+:keywords: sec, tcpdump
+:data-uri:
+:toc: right
+:toc-title: Table of Contents
+:toclevels: 4
+:source-highlighter: highlight
+:icons: font
+:sectnums: 
+
+
+
+{empty} +
+
+== Network_Analysis
+
+.Network analysis!
+****
+*tcpdump* is a common packet analyzer that runs under the command line. It allows the user to display TCP/IP and other packets being transmitted or received over a network to which the computer is attached. Distributed under the BSD license, tcpdump is free software.
+
+http://docs.swarmlab.io/labs/os2/network-analysis.adoc.html[Network analysis^]
+****
+
+
+
+
+
+:hardbreaks:
+
+{empty} +
+{empty} +
+{empty} 
+
+:!hardbreaks:
+
+'''
+
diff --git a/labs/os2/network-analysis.adoc b/labs/os2/network-analysis.adoc
new file mode 100644
index 0000000..56fb395
--- /dev/null
+++ b/labs/os2/network-analysis.adoc
@@ -0,0 +1,272 @@
+= Network analysis !
+Apostolos rootApostolos@swarmlab.io
+// Metadata:
+:description:  network analysis
+:keywords: sec, tcpdump
+:data-uri:
+:toc: right
+:toc-title: Table of Contents
+:toclevels: 4
+:source-highlighter: highlight
+:icons: font
+:sectnums: 
+
+
+
+{empty} +
+
+
+
+
+**tcpdump** is a common packet analyzer that runs under the command line. It allows the user to display TCP/IP and other packets being transmitted or received over a network to which the computer is attached. Distributed under the BSD license, tcpdump is free software. 
+
+https://en.wikipedia.org/wiki/Tcpdump[More: wikipedia]
+
+== Basic
+
+=== Everything on an interface
+
+Just see what’s going on, by looking at what’s hitting your interface.
+
+[source,bash]
+----
+tcpdump -i eth0
+----
+
+=== Find Traffic by IP
+
+One of the most common queries, using host, you can see traffic that’s going to or from 1.1.1.1.
+
+[source,bash]
+----
+tcpdump host 1.1.1.1
+----
+
+
+=== Filtering by Source and/or Destination
+
+If you only want to see traffic in one direction or the other, you can use src and dst.
+
+[source,bash]
+----
+tcpdump src 1.1.1.1
+tcpdump dst 1.0.0.1
+----
+
+=== Finding Packets by Network
+
+To find packets going to or from a particular network or subnet, use the net option.
+
+[source,bash]
+----
+tcpdump net 1.2.3.0/24
+----
+
+
+=== Show Traffic Related to a Specific Port
+
+You can find specific port traffic by using the port option followed by the port number.
+
+[source,bash]
+----
+tcpdump port 3389
+tcpdump src port 1025
+----
+
+=== Show Traffic of One Protocol
+
+If you’re looking for one particular kind of traffic, you can use tcp, udp, icmp, and many others as well.
+
+[source,bash]
+----
+tcpdump icmp
+----
+
+=== Reading / Writing Captures to a File (pcap)
+
+It’s often useful to save packet captures into a file for analysis in the future. These files are known as PCAP (PEE-cap) files, and they can be processed by hundreds of different applications, including network analyzers, intrusion detection systems, and of course by tcpdump itself. Here we’re writing to a file called capture_file using the -w switch.
+
+
+[source,bash]
+----
+tcpdump port 80 -w capture_file
+----
+
+
+== Advanced
+
+
+Now that we’ve seen what we can do with the basics through some examples, let’s look at some more advanced stuff.
+
+.More options
+[source,bash]
+----
+  -X         : Show the packet’s contents in both hex and ASCII.
+  -XX        : Same as -X, but also shows the ethernet header.
+  -D         : Show the list of available interfaces
+  -l         : Line-readable output (for viewing as you save, or sending to other commands)
+  -q         : Be less verbose (more quiet) with your output.
+  -t         : Give human-readable timestamp output.
+  -tttt      : Give maximally human-readable timestamp output.
+  -i eth0    : Listen on the eth0 interface.
+  -vv        : Verbose output (more v’s gives more output).
+  -c         : Only get x number of packets and then stop.
+  -s         : Define the snaplength (size) of the capture in bytes. Use -s0 to get everything, unless you are intentionally capturing less.
+  -S         : Print absolute sequence numbers.
+  -e         : Get the ethernet header as well.
+  -q         : Show less protocol information.
+  -E         : Decrypt IPSEC traffic by providing an encryption key.
+----
+
+
+[NOTE]
+====
+It’s All About the Combinations
+
+Being able to do these various things individually is powerful, but the real magic of tcpdump comes from the ability to combine options in creative ways in order to isolate exactly what you’re looking for. There are three ways to do combinations, and if you’ve studied programming at all they’ll be pretty familiar to you.
+
+- AND
+
+    and or &&
+
+- OR
+
+    or or ||
+
+- EXCEPT
+
+    not or !
+====
+
+
+=== From specific IP and destined for a specific Port
+
+Let’s find all traffic from 10.5.2.3 going to any host on port 3389.
+
+[source,bash]
+----
+tcpdump -nnvvS src 10.5.2.3 and dst port 3389
+----
+
+
+=== From One Network to Another
+
+Let’s look for all traffic coming from 192.168.x.x and going to the 10.x or 172.16.x.x networks, and we’re showing hex output with no hostname resolution and one level of extra verbosity.
+
+[source,bash]
+----
+tcpdump -nvX src net 192.168.0.0/16 and dst net 10.0.0.0/8 or 172.16.0.0/16
+----
+
+
+=== Isolate TCP Flags
+
+You can also use filters to isolate packets with specific TCP flags set.
+
+==== Isolate TCP RST flags.
+
+The filters below find these various packets because tcp[13] looks at offset 13 in the TCP header, the number represents the location within the byte, and the !=0 means that the flag in question is set to 1, i.e. it’s on.
+
+[source,bash]
+----
+tcpdump 'tcp[13] & 4!=0'
+tcpdump 'tcp[tcpflags] == tcp-rst'
+----
+
+==== Isolate TCP SYN flags.
+
+[source,bash]
+----
+tcpdump 'tcp[13] & 2!=0'
+tcpdump 'tcp[tcpflags] == tcp-syn'
+----
+
+==== Isolate packets that have both the SYN and ACK flags set.
+
+[source,bash]
+----
+tcpdump 'tcp[13]=18'
+----
+
+[NOTE]
+====
+Only the PSH, RST, SYN, and FIN flags are displayed in tcpdump‘s flag field output. URGs and ACKs are displayed, but they are shown elsewhere in the output rather than in the flags field.
+====
+
+==== Isolate TCP URG flags.
+
+[source,bash]
+----
+tcpdump 'tcp[13] & 32!=0'
+tcpdump 'tcp[tcpflags] == tcp-urg'
+----
+
+==== Isolate TCP ACK flags.
+
+[source,bash]
+----
+tcpdump 'tcp[13] & 16!=0'
+tcpdump 'tcp[tcpflags] == tcp-ack'
+----
+
+==== Isolate TCP PSH flags.
+
+[source,bash]
+----
+tcpdump 'tcp[13] & 8!=0'
+tcpdump 'tcp[tcpflags] == tcp-psh'
+----
+
+==== Isolate TCP FIN flags.
+
+[source,bash]
+----
+tcpdump 'tcp[13] & 1!=0'
+tcpdump 'tcp[tcpflags] == tcp-fin'
+----
+
+
+=== Find Traffic With Evil Bit
+
+There’s a bit in the IP header that never gets set by legitimate applications, which we call the “Evil Bit”. Here’s a fun filter to find packets where it’s been toggled.
+
+[source,bash]
+----
+tcpdump 'ip[6] & 128 != 0'
+----
+
+=== Summary
+
+Here are the takeaways.
+
+[NOTE]
+====
+- **tcpdump** is a valuable tool for anyone looking to get into networking or **information security**.
+- The raw way it interfaces with traffic, combined with the precision it offers in inspecting packets make **it the best possible tool** for learning TCP/IP.
+- Protocol Analyzers like **Wireshark** are great, but if you want to truly master **packet-fu**, you must become one with tcpdump 
+====
+
+
+[appendix]
+== How to use tcpdump
+
+
+This exercise will show you how to isolate traffic in various ways—from IP, to port, to protocol, to application-layer traffic—to make sure you find exactly what you need as quickly as possible.
+
+https://danielmiessler.com/study/tcpdump[Origin]
+
+
+
+
+
+
+:hardbreaks:
+
+{empty} +
+{empty} +
+{empty} 
+
+:!hardbreaks:
+
+'''
+
diff --git a/labs/os2/scan-and-network-statistics.adoc b/labs/os2/scan-and-network-statistics.adoc
new file mode 100644
index 0000000..be7194c
--- /dev/null
+++ b/labs/os2/scan-and-network-statistics.adoc
@@ -0,0 +1,350 @@
+= Scan and network statistics !
+Apostolos rootApostolos@swarmlab.io
+// Metadata:
+:description: os
+:keywords: scan network statistics
+:data-uri:
+:toc: right
+:toc-title: Table of Contents
+:toclevels: 4
+:source-highlighter: highlight
+:icons: font
+:sectnums: 
+
+
+
+{empty} +
+
+
+
+== Find IP
+
+[source,bash]
+----
+# ifconfig
+
+eth0:   flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
+        inet 172.21.0.2  netmask 255.255.0.0  broadcast 172.21.255.255
+        ether 02:42:ac:15:00:02  txqueuelen 0  (Ethernet)
+        RX packets 61  bytes 9309 (9.3 KB)
+        RX errors 0  dropped 0  overruns 0  frame 0
+        TX packets 0  bytes 0 (0.0 B)
+        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
+
+lo:     flags=73<UP,LOOPBACK,RUNNING>  mtu 65536
+        inet 127.0.0.1  netmask 255.0.0.0
+        loop  txqueuelen 1000  (Local Loopback)
+        RX packets 248  bytes 14260 (14.2 KB)
+        RX errors 0  dropped 0  overruns 0  frame 0
+        TX packets 248  bytes 14260 (14.2 KB)
+        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
+---- 
+
+TIP: inet ***172.21.0.2***  netmask 255.255.0.0  broadcast 172.21.255.255
+
+== Find live hosts
+
+[source,bash]
+----
+nmap -sP 172.21.0.*
+
+Nmap scan report for 172.21.0.1 (172.21.0.1)
+Host is up (0.00028s latency).
+MAC Address: 02:42:56:48:D0:61 (Unknown)
+Nmap scan report for testnetwork2_worker_1.testnetwork2_net (172.21.0.3)
+Host is up (0.00015s latency).
+MAC Address: 02:42:AC:15:00:03 (Unknown)
+Nmap scan report for testnetwork2_worker_3.testnetwork2_net (172.21.0.4)
+Host is up (0.00018s latency).
+MAC Address: 02:42:AC:15:00:04 (Unknown)
+Nmap scan report for testnetwork2_worker_4.testnetwork2_net (172.21.0.5)
+Host is up (0.00015s latency).
+MAC Address: 02:42:AC:15:00:05 (Unknown)
+Nmap scan report for testnetwork2_worker_2.testnetwork2_net (172.21.0.6)
+Host is up (0.00017s latency).
+MAC Address: 02:42:AC:15:00:06 (Unknown)
+Nmap scan report for 9110d42e466b (172.21.0.2)
+
+
+nmap -sP 172.21.0.* | grep Nmap | cut -d' ' -f5-6
+
+172.21.0.1 (172.21.0.1)
+testnetwork2_worker_1.testnetwork2_net (172.21.0.3)
+testnetwork2_worker_3.testnetwork2_net (172.21.0.4)
+testnetwork2_worker_4.testnetwork2_net (172.21.0.5)
+testnetwork2_worker_2.testnetwork2_net (172.21.0.6)
+9110d42e466b (172.21.0.2)
+
+----
+
+.What is Nmap?
+[NOTE]
+====
+Nmap, short for Network Mapper, is a free, open-source tool for vulnerability scanning and network discovery. Network administrators use Nmap to identify what devices are running on their systems, discovering hosts that are available and the services they offer, finding open ports and detecting security risks.
+
+See https://en.wikipedia.org/wiki/Nmap
+====
+
+
+
+== Scan Ports
+
+=== Scan a Single Port, All Ports, or Series
+
+[source,bash]
+----
+Nmap commands can be used to scan a single port or a series of ports:
+----
+
+=== Scan port 80 on the target system:
+
+[source,bash]
+----
+nmap –p 80 172.21.0.3
+----
+
+=== Scan ports 1 through 200 on the target system:
+
+[source,bash]
+----
+nmap –p 1-200 172.21.0.3
+----
+
+=== Scan (Fast) the most common ports:
+
+[source,bash]
+----
+nmap –F 172.21.0.3
+----
+
+=== To scan all ports (1 – 65535):
+
+[source,bash]
+----
+nmap –p– 172.21.0.3
+----
+
+
+
+=== Scan All TCP UDP Ports
+
+Scan all UDP and TCP ports in a single command. We will use -sU for UDP and sT for TCP protocol.
+[source,bash]
+----
+nmap -sU -sT -p0-65535 IP
+----
+
+
+.What Are Ports?
+[NOTE]
+====
+
+On modern operating systems, ports are numbered addresses for network traffic. Different kinds of services use different ports by default.
+
+For example, normal web traffic uses Port 80, while POP3 email uses Port 110. One of the ways that a firewall works is by allowing or restricting traffic over a particular port.
+
+Because the ports into your computer can cause a security risk, it’s critical to know which ports are open and which are blocked.
+
+====
+
+== netstat
+
+=== Listing  (Almost all)
+
+[source,bash]
+----
+netstat -antlupe
+----
+
+=== Listing TCP Ports connections
+
+[source,bash]
+----
+netstat -at
+----
+
+.Netstat
+[NOTE]
+====
+Netstat command displays various network related information such as network connections, routing tables, interface statistics, masquerade connections, multicast memberships etc.,
+====
+
+
+=== Listing UDP Ports connections
+
+[source,bash]
+----
+netstat -au
+----
+
+
+=== Listing all LISTENING Connections
+
+[source,bash]
+----
+netstat -l
+----
+
+
+=== Listing all TCP Listening Ports
+
+[source,bash]
+----
+netstat -lt
+----
+
+=== Listing all UDP Listening Ports
+
+[source,bash]
+----
+netstat -lu
+----
+
+
+=== Listing all UNIX Listening Ports
+
+[source,bash]
+----
+netstat -lx
+----
+
+
+=== Showing Statistics by Protocol
+
+[source,bash]
+----
+netstat -s
+----
+
+=== Showing Statistics by TCP Protocol
+
+[source,bash]
+----
+netstat -st
+----
+
+=== Showing Statistics by UDP Protocol
+
+[source,bash]
+----
+netstat -su
+----
+
+=== Displaying Service name with PID
+
+[source,bash]
+----
+netstat -tp
+----
+
+
+=== Displaying Promiscuous Mode
+
+Displaying Promiscuous mode with -ac switch, netstat print the selected information or refresh screen every five second. Default screen refresh in every second. + 
+
+[source,bash]
+----
+ netstat -ac 5 | grep tcp
+----
+
+=== Setting Promiscuous Mode
+
+[source,bash]
+----
+ ifconfig eth0 promisc
+
+OR
+
+ip link set eth0 promisc on
+----
+
+=== Remove Promiscuous Mode
+
+[source,bash]
+----
+ ifconfig eth0 –promisc
+----
+
+
+.Promiscuous Mode
+[NOTE]
+====
+Promiscuous mode is a mode for a wired network interface controller (NIC) or wireless network interface controller (WNIC) that causes the controller to pass all traffic it receives to the central processing unit (CPU) rather than passing only the frames that the controller is specifically programmed to receive. 
+
+When a capable NIC is placed in Promiscuous Mode, it allows the NIC to intercept and read each arriving network packet in its entirety. 
+
+If the NIC is not in Promiscuous Mode, it will only receive packets that are specifically addressed to the NIC. Promiscuous Mode must be supported by the NIC and by the operating system and any associated driver. Not all NICs support Promiscuous Mode, however it is pretty easy to determine if you have a NIC and OS capable of Promiscuous Mode.
+====
+
+
+=== check if promiscuous mode is enabled on network interface
+
+[source,bash]
+----
+
+netstat -i
+
+Iface      MTU    RX-OK RX-ERR RX-DRP RX-OVR    TX-OK TX-ERR TX-DRP TX-OVR Flg
+eth0      1500     8352      0      0 0         12677      0      0      0 BMRU
+lo       65536    14656      0      0 0         14656      0      0      0 LRU
+
+ifconfig eth0 promisc
+
+netstat -i
+
+Iface      MTU    RX-OK RX-ERR RX-DRP RX-OVR    TX-OK TX-ERR TX-DRP TX-OVR Flg
+eth0      1500     8352      0      0 0         12677      0      0      0 BMPRU
+lo       65536    14696      0      0 0         14696      0      0      0 LRU
+
+ifconfig eth0 -promisc
+
+netstat -i
+
+Iface      MTU    RX-OK RX-ERR RX-DRP RX-OVR    TX-OK TX-ERR TX-DRP TX-OVR Flg
+eth0      1500     8353      0      0 0         12677      0      0      0 BMRU
+lo       65536    15232      0      0 0         15232      0      0      0 LRU
+
+
+----
+
+.Promiscuous Mode
+[NOTE]
+====
+Look under the last column “Flg” for value “P”. If it’s there, it means promiscuous mode is enabled for that network interface + 
+B flag is for broadcast + 
+M flag is for multicast + 
+P flag is for promisc mode + 
+R is for running + 
+U is for up + 
+
+====
+
+
+
+
+[appendix]
+== How to use Nmap
+
+While the basis of Nmap's functionality is port scanning, it allows for a variety of related capabilities including:
+
+- Network mapping: Nmap can identify the devices on a network (also called host discovery), including servers, routers and switches, and how they're physically connected.
+- OS detection: Nmap can detect the operating systems running on network devices (also called OS fingerprinting), providing the vendor name, the underlying operating system, the version of the software and even an estimate of devices' uptime.
+- Service discovery: Nmap can not only identify hosts on the network, but whether they're acting as mail, web or name servers, and the particular applications and versions of the related software they're running.
+- Security auditing: Figuring out what versions of operating systems and applications are running on network hosts lets network managers determine their vulnerability to specific flaws. If a network admin receives an alert about a vulnerability in a particular version of an application, for example, she can scan her network to identify whether that software version is running on the network and take steps to patch or update the relevant hosts. Scripts can also automate tasks such as detecting specific vulnerabilities.
+
+
+
+
+
+
+
+
+:hardbreaks:
+
+{empty} +
+{empty} +
+{empty} 
+
+:!hardbreaks:
+
+'''
diff --git a/labs/os2/sec.adoc b/labs/os2/sec.adoc
new file mode 100644
index 0000000..aa30d08
--- /dev/null
+++ b/labs/os2/sec.adoc
@@ -0,0 +1,157 @@
+= Ασφάλεια Δικτύων και Επικοινωνιών !
+Apostolos rootApostolos@swarmlab.io
+// Metadata:
+:description: Intro and Install
+:keywords: sec, iptables
+:data-uri:
+:toc: right
+:toc-title: Πίνακας περιεχομένων
+:toclevels: 4
+:icons: font
+:source-highlighter: highlight
+:sectnums: 
+
+
+include::header.adoc[]
+
+
+
+
+{empty} +
+
+
+[[cheat-Docker]]
+== Install swarmlab-sec (Home PC)
+
+- Install docker + 
+http://docs.swarmlab.io/Howtos/docker/install.adoc.html[^]
+
+- Clone repo https://git.swarmlab.io:3000/swarmlab/swarmlab-sec + 
+HowTo: See http://docs.swarmlab.io/Howtos/git/use-git.adoc.html 
+
+.INSTALL
+[NOTE]
+====
+See INSTALL.md for Installation Instruction
+====
+
+.lab
+[NOTE]
+====
+In Lab's everything is ready!
+Goto  "create"
+====
+
+[[cheat-swarmlab-sec]]
+== Usage  (swarmlab-sec)
+
+
+- Open a console
+
+- Create a directory
+
+```
+cd dir
+swarmlab-sec <tab><tab>
+
+create       create project      (swarmlab-sec create)
+up           start swarmlab-sec  (swarmlab-sec up size=10)
+scale        resize swarmlab-sec (swarmlab-sec scale size=30)
+reload       rebuild image       (swarmlab-sec reload size=15)
+login        login swarmlab-sec  (swarmlab-sec login)
+exec         execute command     (swarmlab-sec exec [SHELL COMMAND])
+down         stop swarmlab-sec   (swarmlab-sec down)
+clean        clean project       (swarmlab-sec clean)
+list         show instances      (swarmlab-sec swarmlab-sec list)
+help         show help           (swarmlab-sec help)
+```
+
+[NOTE]
+====
+Using the tab key to automatically complete unambiguous commands and paths in Bash
+====
+
+
+[[cheat-swarmlab-create]]
+== Create swarmlab project
+
+```
+mkdir myproject
+cd myproject
+swarmlab-sec create
+```
+.Relevant files:
+```
+Project
+├── Dockerfile          # Image specification
+├── project             # Sample program source code
+│   └── hello_world.c
+├── ssh                 # keys for accessing
+│   ├── id_rsa          # (could generate your own)
+│   └── id_rsa.pub
+├── docker-compose.yml  # Container orchestration 
+```
+
+[[cheat-swarmlab-up]]
+== Spin up the swarmlab cluster
+
+```
+cd myproject
+swarmlab-sec up size=5
+```
+
+
+.We built a high-performing, scalable infrastructure
+image:./swarmlab-network.png[alt="Swarmlab"] +
+
+
+[[cheat-swarmlab-up1]]
+== Login to the swarmlab cluster
+
+```
+cd myproject
+swarmlab-sec login
+```
+
+
+[[cheat-swarmlab-scale]]
+== Scale cluster in real-time
+
+As the cluster running, without having to close the session, open a different terminal and go back to the project directory.
+
+```
+cd myproject
+swarmlab-sec scale size=10
+```
+
+[[cheat-swarmlab-down]]
+== shutdown swarmlab-sec cluster
+
+
+```
+cd myproject
+swarmlab-sec down
+```
+
+:hardbreaks:
+
+{empty} +
+{empty} +
+{empty} 
+
+:!hardbreaks:
+
+'''
+
+.Reminder
+[NOTE]
+====
+:hardbreaks:
+Caminante, no hay camino, 
+se hace camino al andar.
+
+Wanderer, there is no path, 
+the path is made by walking.
+
+*Antonio Machado* Campos de Castilla
+====
diff --git a/labs/os2/ssh-tunneling-1366x416-WPhEwBvP.png b/labs/os2/ssh-tunneling-1366x416-WPhEwBvP.png
new file mode 100644
index 0000000..3b3e135
Binary files /dev/null and b/labs/os2/ssh-tunneling-1366x416-WPhEwBvP.png differ
diff --git a/labs/os2/ssh-tunneling.adoc b/labs/os2/ssh-tunneling.adoc
new file mode 100644
index 0000000..48a8160
--- /dev/null
+++ b/labs/os2/ssh-tunneling.adoc
@@ -0,0 +1,245 @@
+= SSH Tunneling!
+Apostolos rootApostolos@swarmlab.io
+// Metadata:
+:description: Intro and Install
+:keywords: sec, tcpdump
+:data-uri:
+:toc: right
+:toc-title: Table of Contents
+:toclevels: 4
+:source-highlighter: highlight
+:icons: font
+:sectnums: 
+
+
+
+{empty} +
+
+
+
+
+
+== SSH Tunneling
+
+***SSH Tunneling***, is the ability to use ssh to create a bi-directional encrypted network connection between machines over which data can be exchanged, typically TCP/IP.
+
+
+image::ssh-tunneling-1366x416-WPhEwBvP.png[SSH tunneling]
+
+.NOTE
+[NOTE]
+====
+SSH is a standard for secure remote logins and file transfers over untrusted networks. It also provides a way to secure the data traffic of any given application using port forwarding, basically tunneling any TCP/IP port over SSH. This means that the application data traffic is directed to flow inside an encrypted SSH connection so that it cannot be eavesdropped or intercepted while it is in transit. SSH tunneling enables adding network security to legacy applications that do not natively support encryption.
+====
+
+
+== Local Port Forwarding
+
+
+.local port forwarding
+[source,bash]
+----
+ssh -nNT -L 8000:localhost:3306 user@192.168.89.5
+----
+
+The above command sets up an ssh tunnel between your machine and the server, and forwards all traffic from localhost:3306 to localhost:8000 (on your machine).
+
+So now you could connect to MySQL running on your server via localhost on port 8000 on your machine.
+
+
+== Remote Port Forwarding
+
+.remote port forwarding
+[source,bash]
+----
+ssh -nNT -R 4000:localhost:3000 user@192.168.89.5
+----
+
+The above command sets up an ssh tunnel between your machine and the server, and forwards all traffic from localhost:3000 (on your machine) to localhost:4000 (in the context of the server). 
+
+So now you can connect to the locally running service on port 3000 on the server on port 4000
+
+
+== SSH Command
+
+
+Practically every Linux system includes the ssh command. This command is used to start the SSH client program that enables secure connection to the SSH server on a remote machine. The ssh command is used from logging into the remote machine, transferring files between the two machines, and for executing commands on the remote machine.
+
+
+=== Connect to server
+
+.connect
+[source,bash]
+----
+ssh  user@192.168.89.5
+
+The authenticity of host '192.168.89.5' cannot be established.
+DSA key fingerprint is 04:48:30:31:b0:f3:5a:9b:01:9d:b3:a7:38:e2:b1:0c.
+Are you sure you want to continue connecting (yes/no)?
+----
+
+Type yes to continue. This will add the server to your list of known hosts (~/.ssh/known_hosts) as seen in the following message:
+
+[source,bash]
+----
+Warning: Permanently added '192.168.89.5' (DSA) to the list of known hosts.
+----
+
+Each server has a host key, and the above question related to verifying and saving the host key, so that next time you connect to the server, it can verify that it actually is the same server.
+
+
+=== Executing remote commands on the server
+
+[source,bash]
+----
+ssh user@192.168.89.5 /bin/bash -c "ls -al"
+----
+
+
+== sshd_config - SSH Server Configuration
+
+The OpenSSH server reads a configuration file when it is started. Usually this file is /etc/ssh/sshd_config, but the location can be changed using the -f command line option when starting sshd.
+
+=== Cryptographic policy
+
+- Symmetric algorithms for encrypting the bulk of transferred data are configured using the Ciphers option. A good value is aes128-ctr,aes192-ctr,aes256-ctr.
+
+- Host key algorithms are selected by the HostKeyAlgorithms option. A good value is ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,ssh-rsa,ssh-dss.
+
+- Key exchange algorithms are selected by the KexAlgorithms option. recommend ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group14-sha1,diffie-hellman-group-exchange-sha256. 
+
+[NOTE]
+====
+not recommend allowing diffie-hellman-group1-sha1, unless needed for compatibility. It uses a 768 bit prime number, which is too small by today's standards and may be breakable by intelligence agencies in real time. Using it could expose connections to man-in-the-middle attacks when faced with such adversaries.
+====
+
+=== Verbose logging
+
+It is strongly recommended that LogLevel be set to VERBOSE. This way, the key fingerprint for any SSH key used for login is logged. This information is important for SSH key management, especially in legacy environments.
+
+[source,bash]
+----
+LogLevel VERBOSE
+----
+
+=== Root login
+
+root access should generally go through a privileged access management system
+
+To disable passwords for root, but still allow key-based access without forced command, use:
+
+[source,bash]
+----
+PermitRootLogin prohibit-password
+----
+
+To disable passwords and only allow key-based access with a forced command, use:
+
+[source,bash]
+----
+PermitRootLogin forced-commands-only
+----
+
+
+=== Port forwarding
+
+Generally prevent port forwarding on servers, unless expressly needed for tunneling legacy applications. 
+There is substantial risk that users will use SSH tunneling to open backdoors into the organization through the firewall to get access to work machines from home.
+
+
+=== Generate a key pair 
+
+
+[source,bash]
+----
+ssh-keygen
+----
+
+Output:
+
+[source,bash]
+----
+Generating public/private rsa key pair.
+Enter file in which to save the key (/home/user/.ssh/id_rsa): 
+Created directory '/home/user/.ssh'.
+Enter passphrase (empty for no passphrase): 
+Enter same passphrase again: 
+Your identification has been saved in /home/user/.ssh/id_rsa.
+Your public key has been saved in /home/user/.ssh/id_rsa.pub.
+The key fingerprint is:
+8c:2a:ed:82:98:6d:12:0a:3a:ba:b2:1c:c0:25:be:5b
+----
+
+
+=== Install your public key 
+
+[source,bash]
+----
+sh-copy-id -i ~/.ssh/id_rsa.pub UserName@RemoteServer
+----
+
+Output:
+
+[source,bash]
+----
+UserName@RemoteServer's password: ********
+----
+
+Now try logging into the machine, with "ssh 'username@remoteserver'", and check in:
+
+[source,bash]
+----
+~/.ssh/authorized_keys
+----
+
+
+== run graphics applications remotely 
+
+X11 forwarding needs to be enabled on both the client side and the server side.
+
+- On the client side, the -X (capital X) option to ssh enables X11 forwarding
+
+- On the server side, X11Forwarding yes must specified in /etc/ssh/sshd_config. 
+
+- The xauth program must be installed on the server side. 
+
+
+[source,bash]
+----
+ssh -X user@192.168.89.5 gimp
+----
+
+== Copy Files and Directories Between Two Systems
+
+=== Copy  a file from a local to a remote system 
+
+
+To copy a file from a local to a remote system run the following command:
+
+[source,bash]
+----
+scp file.txt user@192.168.89.5:/remote/directory
+----
+
+=== Copy a Remote File to a Local System using the scp ommand
+
+
+To copy a file named file.txt from a remote server with IP 192.168.89.5 run the following command:
+
+[source,bash]
+----
+scp user@192.168.89.5:/remote/file.txt /local/directory
+----
+
+
+
+:hardbreaks:
+
+{empty} +
+{empty} +
+{empty} 
+
+:!hardbreaks:
+
+'''
+
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