Logging and Monitoring - Logging Solution - Graylog

Team:
Artur Ovtsinnikov,
Mohanad Aly,
Etienne Barrier,
Meelis Hass

Group : Cyber Security Engineering (C21)

Page Created: 18 September 2016

‎Last modified: ‎ 28 September 2016

= Aim of this page =
The Aim of this wiki page is to give an introduction to Logging and Monitoring application called Graylog, what are the main benefits of it and how to install it on Ubuntu Machine.

*'''logging and monitoring.'''
*'''The best solution for logging'''
*'''Why we should logging our servers'''
*'''Securing during logging'''

=Topology of the Elab system=


'''Desktop machine'''

[[File:Screenshot from 2016-09-18 17-43-55.jpg|thumb|right|Topology []]]
Begin with the basic setup, network configuration and make the machine has internet access which the ip address of the machine is 192.168.56.100


'''Server machine ip address 192.168.56.200'''
*Can be connected over ssh with student@192.168.56.200
*Also can connect with other IP address ssh student@10.10.10.10

'''IDS ip address 192.168.56.201'''

=Starting to update and upgrade for all machines on the Elab=
If your machine is running older version then 16.04 which is the latest long term supported version, please follow the following commands to upgrade your machine to the latest version.
*First check your machine
<code>lsb_release -a</code>

If you found your machine

Description:Ubuntu 16.04.1 LTS

Release:16.04

Then no need to do the next steps

*First be super user
<code>sudo -i</code>

*Begin by updating the package list
<code>apt-get update</code>

*Upgrade installed packages to their latest available versions
<code>apt-get upgrade</code>

*Once upgrade finishes, use the dist-upgrade command, which will perform upgrades involving changing dependencies
<code>apt-get dist-upgrade</code>

*Now that you have an up-to-date installation of Ubuntu 15.10, you can use <code> do-release-upgrade</code> to upgrade to the 16.04 release.

= Initial Setup for graylog=
==== Prerequisites ====
Ubuntu Linux machine, sudo access and some Linux beginner skills are needed.
The installation of Graylog is not that hard as described on some webpages.
In this tutorial the Ubuntu 16.04 64-bit VPS server will be used since it is the latest LTS.
Unfortunately, Graylog cannot be installed simply by using one command apt-get install graylog, because there is some prerequisite applications needed for it to work.
In this tutorial i will describe the commands, what is needed and how to configure the services to work together with the Graylog, installation is simple!
Attention! All links and packages/versions are present to the time of writing this guide it might need to be updated later on.

=== Step by Step Installation tutorial on Ubuntu 16.04 Linux host machine ===
'''1)''' It is important to have the latest package lists to update them to get info on the newst versions of packages and their dependencies. So we need to run the following command to update them:

''Command:'' <code> sudo apt-get update</code>

'''2)''' Now we can install the setup base packages:

''Command:'' <code> apt-get install apt-transport-https openjdk-8-jre-headless uuid-runtime pwgen </code>

'''3)''' '''MongoDB''' is a Free and open-source cross-platform document-oriented database program written in C++,C and JavaScript. Classified as a NoSQL database program in favor of JSON-like documents with dynamic schemas (format BSON) making the integration of data in certain types of applications like Graylog easier and faster.

The version included in Ubuntu 16.04 LTS can be used together with Graylog 2 and higher, but it is also possible to check the [https://www.mongodb.com/download-center?jmp=nav#community official webpage] and download the needed/latest version.

It can be installed by running the following command:

''Command:'' <code> apt-get install mongodb-server </code>

'''4)''' '''Elasticsearch''' is a search engine based on Lucene written in Java. It provides a distributed, multitenant-capable full-text search engine with an HTTP web interface and schema-free JSON documents.

Elasticsearch is required for Graylog 2 and higher to work, so it is possible to see the complete installation instructions on the [https://www.elastic.co/guide/en/elasticsearch/reference/2.3/setup-repositories.html#_apt official page]

''Commands:''

<code>wget -qO - https://packages.elastic.co/GPG-KEY-elasticsearch | sudo apt-key add -</code>

<code>echo "deb https://packages.elastic.co/elasticsearch/2.x/debian stable main" | sudo tee -a /etc/apt/sources.list.d/elasticsearch-2.x.list</code>

<code>sudo apt-get update</code>

<code>sudo apt-get install elasticsearch</code>

'''5)''' Modifying the Elasticsearch configuration file and setting the cluster name to graylog so it will be visible and accessible by graylog.

''Command:'' <code> nano /etc/elasticsearch/elasticsearch.yml</code>
and change <code> cluster.name:elasticsearch</code> to <code> cluster.name: graylog</code>

'''6)''' After config was modified, we can now start Elasticsearch:

<code>sudo /bin/systemctl daemon-reload</code>

<code>sudo /bin/systemctl enable elasticsearch.service</code>

<code>sudo /bin/systemctl restart elasticsearch.service</code>

It is possible to check if the elasticsearch configured correctly by using the following command:

<code>curl -XGET http://localhost:9200</code>

'''7)''' '''Graylog''' can now be installed if all the above steps were done successfully
First it is needed to install the Graylog repository using the following commands:

<code>wget https://packages.graylog2.org/repo/packages/graylog-2.1-repository_latest.deb</code>

<code>sudo dpkg -i graylog-2.1-repository_latest.deb</code>

<code>sudo apt-get update</code>

<code>sudo apt-get install graylog-server</code>

'''8)''' After the Graylog has been installed it is needed to change the configuration

Think about the password (which would be used to login) and then use the command:
<code>echo -n supersecretpassword123 | sha256sum</code>
It will generate the sha256 hash of the password which would be needed to copy-pasted and add it to the <code>password_secret</code> and <code>root_password_sha2</code> in the graylog config (<code>/etc/graylog/server/server.conf</code>). This is mandatory to do! Without it Graylog will not start!

'''9)''' In order to connect to Graylog web-interface it is needed to set <code>rest_listen_uri</code> and <code>web_listen_uri</code> to the public hostname or IP address of the machine.

'''10)''' Last step is to enable Graylog during the system startup:

<code>sudo systemctl daemon-reload</code>

<code>sudo systemctl enable graylog-server.service</code>

<code>sudo systemctl start graylog-server.service</code>

=Summary=

=See also=

=References=

------

[[Category:Logging and monitoring]]

Logging&monitoring

2016-10-05T19:48:01Z

Aovtsinn: /* Starting to update and upgrade for all machines on the Elab */

Logging and Monitoring - Logging Solution - Graylog

Team:
Artur Ovtsinnikov,
Mohanad Aly,
Etienne Barrier,
Meelis Hass

Group : Cyber Security Engineering (C21)

Page Created: 18 September 2016

‎Last modified: ‎ 28 September 2016

= Aim of this page =
The Aim of this wiki page is to give an introduction to Logging and Monitoring application called Graylog, what are the main benefits of it and how to install it on Ubuntu Machine.

*'''logging and monitoring.'''
*'''The best solution for logging'''
*'''Why we should logging our servers'''
*'''Securing during logging'''

=Topology of the Elab system=


'''Desktop machine'''

[[File:Screenshot from 2016-09-18 17-43-55.jpg|thumb|right|Topology []]]
Begin with the basic setup, network configuration and make the machine has internet access which the ip address of the machine is 192.168.56.100


'''Server machine ip address 192.168.56.200'''
*Can be connected over ssh with student@192.168.56.200
*Also can connect with other IP address ssh student@10.10.10.10

'''IDS ip address 192.168.56.201'''

=Starting to update and upgrade for all machines on the Elab=
If your machine is running older version then 16.04.1 which is the latest long term supported version, please follow the following commands to upgrade your machine to the latest version.
*First check your machine
<code>lsb_release -a</code>

If you found your machine

Description:Ubuntu 16.04.1 LTS

Release:16.04

Then no need to do the next steps

*First be super user
<code>sudo -i</code>

*Begin by updating the package list
<code>apt-get update</code>

*Upgrade installed packages to their latest available versions
<code>apt-get upgrade</code>

*Once upgrade finishes, use the dist-upgrade command, which will perform upgrades involving changing dependencies
<code>apt-get dist-upgrade</code>

*Now that you have an up-to-date installation of Ubuntu 15.10, you can use <code> do-release-upgrade</code> to upgrade to the 16.04 release.

= Initial Setup for graylog=
==== Prerequisites ====
Ubuntu Linux machine, sudo access and some Linux beginner skills are needed.
The installation of Graylog is not that hard as described on some webpages.
In this tutorial the Ubuntu 16.04 64-bit VPS server will be used since it is the latest LTS.
Unfortunately, Graylog cannot be installed simply by using one command apt-get install graylog, because there is some prerequisite applications needed for it to work.
In this tutorial i will describe the commands, what is needed and how to configure the services to work together with the Graylog, installation is simple!
Attention! All links and packages/versions are present to the time of writing this guide it might need to be updated later on.

=== Step by Step Installation tutorial on Ubuntu 16.04 Linux host machine ===
'''1)''' It is important to have the latest package lists to update them to get info on the newst versions of packages and their dependencies. So we need to run the following command to update them:

''Command:'' <code> sudo apt-get update</code>

'''2)''' Now we can install the setup base packages:

''Command:'' <code> apt-get install apt-transport-https openjdk-8-jre-headless uuid-runtime pwgen </code>

'''3)''' '''MongoDB''' is a Free and open-source cross-platform document-oriented database program written in C++,C and JavaScript. Classified as a NoSQL database program in favor of JSON-like documents with dynamic schemas (format BSON) making the integration of data in certain types of applications like Graylog easier and faster.

The version included in Ubuntu 16.04 LTS can be used together with Graylog 2 and higher, but it is also possible to check the [https://www.mongodb.com/download-center?jmp=nav#community official webpage] and download the needed/latest version.

It can be installed by running the following command:

''Command:'' <code> apt-get install mongodb-server </code>

'''4)''' '''Elasticsearch''' is a search engine based on Lucene written in Java. It provides a distributed, multitenant-capable full-text search engine with an HTTP web interface and schema-free JSON documents.

Elasticsearch is required for Graylog 2 and higher to work, so it is possible to see the complete installation instructions on the [https://www.elastic.co/guide/en/elasticsearch/reference/2.3/setup-repositories.html#_apt official page]

''Commands:''

<code>wget -qO - https://packages.elastic.co/GPG-KEY-elasticsearch | sudo apt-key add -</code>

<code>echo "deb https://packages.elastic.co/elasticsearch/2.x/debian stable main" | sudo tee -a /etc/apt/sources.list.d/elasticsearch-2.x.list</code>

<code>sudo apt-get update</code>

<code>sudo apt-get install elasticsearch</code>

'''5)''' Modifying the Elasticsearch configuration file and setting the cluster name to graylog so it will be visible and accessible by graylog.

''Command:'' <code> nano /etc/elasticsearch/elasticsearch.yml</code>
and change <code> cluster.name:elasticsearch</code> to <code> cluster.name: graylog</code>

'''6)''' After config was modified, we can now start Elasticsearch:

<code>sudo /bin/systemctl daemon-reload</code>

<code>sudo /bin/systemctl enable elasticsearch.service</code>

<code>sudo /bin/systemctl restart elasticsearch.service</code>

It is possible to check if the elasticsearch configured correctly by using the following command:

<code>curl -XGET http://localhost:9200</code>

'''7)''' '''Graylog''' can now be installed if all the above steps were done successfully
First it is needed to install the Graylog repository using the following commands:

<code>wget https://packages.graylog2.org/repo/packages/graylog-2.1-repository_latest.deb</code>

<code>sudo dpkg -i graylog-2.1-repository_latest.deb</code>

<code>sudo apt-get update</code>

<code>sudo apt-get install graylog-server</code>

'''8)''' After the Graylog has been installed it is needed to change the configuration

Think about the password (which would be used to login) and then use the command:
<code>echo -n supersecretpassword123 | sha256sum</code>
It will generate the sha256 hash of the password which would be needed to copy-pasted and add it to the <code>password_secret</code> and <code>root_password_sha2</code> in the graylog config (<code>/etc/graylog/server/server.conf</code>). This is mandatory to do! Without it Graylog will not start!

'''9)''' In order to connect to Graylog web-interface it is needed to set <code>rest_listen_uri</code> and <code>web_listen_uri</code> to the public hostname or IP address of the machine.

'''10)''' Last step is to enable Graylog during the system startup:

<code>sudo systemctl daemon-reload</code>

<code>sudo systemctl enable graylog-server.service</code>

<code>sudo systemctl start graylog-server.service</code>

=Summary=

=See also=

=References=

------

[[Category:Logging and monitoring]]

Logging&monitoring

2016-09-28T20:43:23Z

Aovtsinn: /* Initial Setup */

2016-04-03T15:02:10Z

Aovtsinn:

__NOTOC__
[[File:Openvpn2.png|thumb|right|alt=A screenshot of Open VPN Client UI.| Logged in Open VPN Client UI]]

OpenVPN Access Server (OpenVPN-AS) is a set of installation and configuration tools that simplify the rapid deployment of a VPN remote access solution. It is based on the popular OpenVPN open-source software, making the deployed VPN immediately compatible with OpenVPN client software across multiple user platforms. The server configurations options supported are a carefully selected subset of a quite large set of possible OpenVPN configurations. Thus, OpenVPN Access Server streamlines the configuration and management of an OpenVPN-based secure remote access deployment.

== About OpenVPN ==
OpenVPN is an open-source software application that implements virtual private network (VPN) techniques for creating secure point-to-point 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).

=== Overview===
OpenVPN Access Server is a full featured secure network tunneling VPN software solution that integrates OpenVPN server capabilities, enterprise management capabilities, simplified OpenVPN Connect UI, and OpenVPN Client software packages that accommodate Windows, MAC, Linux, Android, and iOS environments. OpenVPN Access Server supports a wide range of configurations, including secure and granular remote access to internal network and/ or private cloud network resources and applications with fine-grained access control.
=== Supported Operation Systems===
OpenVPN currently supports all main operation systems such as Windows, Mac OS X, Android, iOS and Linux It is possible to download software for your machine on the official website or it is possible to get it after installation of Access Server and logging in with your credentials to your ip_address_or_domain_name:943 (port 943 is default can be changed in the config) and it is possible to download after logging in connection profile for autologin or user-locked profile. (possible to change those settings in the Admin panel of OpenVPN Access Server.
=== Pricing===
OpenVPN is a free sorfware application which provides you 2 user license ( which means that 2 users/machines can be using current OpenVPN Access Server at the same time) after installation which is more then enough for a one person to use. Although it is possible to purchase more Licenses on official website for 9.60$ per concurrent user. And minimum license term is for one year.
== Operating system to Host Access Server software==
Currently, the Access Server software must be run on a 32-bit or 64-bit Linux host. The software is released in the form of binary package files for particular Linux distributions. Supported are RedHat, Fedora, CentOS, Ubuntu, Debian and openSUSE (Most RPM packages can be ran on the following systems: CentOS 6 and 7, Fedora 22, RHEL 6, openSUSE 13. The Deb packages can be ran on the following systems: Ubuntu 12, Debian 6,7,8)

== Difference between Community Edition VPN and Access Server==
Both Community Edition and Access Server is provided by OpenVPN and they both have something in common like: Secured VPN Tunnel, GUI Client, Bridging, Configurable Ciphers and Real-time compression. But Access Server provides more options such as Web Based GUI (it is possible to use VPN without need of downloading any additional software), Pre-configured Client (possible to download auto filled profile and Auto-login option available), Automated Certificate Creation (Access server web page will also be protected with encrypted https connection (TLS 1.2, The connection is encrypted and authenticated using AES_128_GCM and uses ECDHE_RSA as the key exchange mechanism.) Easy Deployment, Failover Solution, Simple User Management, Pre-built Virtual Appliances, Fill LDAP support, Easy Scalability, User-mode Client, Multi-daemon mode and DMZ mode.
== Step by Step Installation and configuration tutorial on Ubuntu Linux host machine==
Prerequisites: Ubuntu Linux machine and some Linux beginner skills.
The installation of OpenVPN-AS is simple. In this tutorial I will be using Ubuntu 14.04 64-bit VPS server.
Unfortunately, OpenVPN Assess Server cannot be installed using apt-get install, so we will be downloading installation files by ourselves.

'''1)''' First we would need to become root

''Command:'' <code> sudo su</code>

'''2)''' We would need to download the latest software installation files from official website which can be found here: [https://openvpn.net/index.php/access-server/download-openvpn-as-sw.html Official Download Page] (Click on the needed Operation System and select needed version to download (32 bit or 64 bit and Ubuntu version 12 or 14) then right click on it and copy link)

'''3)''' Now we go back to our console panel and download the OpenVPN Access Server using wget and paste copied link before. File will be downloaded by default to root user home directory. (it is possible to change.) File will be something around 28 MB (my file 64bit Ubuntu Linux)

''Command:'' <code>wget http://swupdate.openvpn.org/as/openvpn-as-2.0.25-Ubuntu12.amd_64.deb </code>

'''4)''' Now we install downloaded file using following command dpkg –i (And downloaded file name)

''Command:'' <code>dpkg –i openvpn-as-2.0.25-Ubuntu12.amd_64.deb</code>

That’s it. OpenVPN AS is now installed. But there is some configurations needed before we can use it.

'''5)''' During the installation OpenVPN created admin user which is by default called “openvpn” but the password left empty for security reasons are are going to change the password using command (as root) after command you will be provided with be promted to enter password. Make sure your password is secure!

''Command:'' <code>passwd openvpn</code>

'''6)''' Now we are going to check the OpenVPN AS web interface which can be found by default port 943 and your ip address, login using username openvpn and password what you set before. (After logging in you would need to click Agree to accept the License Agreement.

Admin page: https://ip_address_or_domain:943/admin

Client page: https://ip_address_or_domain:943/

Note: The server’s SSL is self-signed so not need to worry about the bad security warning

'''7)''' Download needed OpenVPN Connect software by clicking the link. After it has finished downloading, run it and enter your credentials. And connection to your Access Server have been established. You can also download official Android or iOS application to use VPN on your smartphone.
Note: You can also login to Admin Ul page if you want to add users or change settings, although the default settings works fine without any problems.

We are done! Have fun with your OpenVPN Access Server for free and be more secure using this encrypted connection.

Tutorial created by Artur Ovtsinnikov, if you have any questions it is possible to contact me by email.

== See Also==
A bit better Step-by-Step pdf tutorial with screenshots can be downloaded here: LINK

==References==
https://openvpn.net

https://openvpn.net/index.php/access-server/overview.html

https://openvpn.net/index.php/access-server/docs/admin-guides-sp-859543150.html

https://en.wikipedia.org/wiki/OpenVPN

https://en.wikipedia.org/wiki/Pre-shared_key

OpenVPN Access Server

2016-04-03T14:48:48Z

Aovtsinn:

__NOTOC__
[[File:Openvpn2.png|thumb|right|alt=A screenshot of Open VPN Client UI.| Logged in Open VPN Client UI]]

OpenVPN Access Server (OpenVPN-AS) is a set of installation and configuration tools that simplify the rapid deployment of a VPN remote access solution. It is based on the popular OpenVPN open-source software, making the deployed VPN immediately compatible with OpenVPN client software across multiple user platforms. The server configurations options supported are a carefully selected subset of a quite large set of possible OpenVPN configurations. Thus, OpenVPN Access Server streamlines the configuration and management of an OpenVPN-based secure remote access deployment.

== About OpenVPN ==
OpenVPN is an open-source software application that implements virtual private network (VPN) techniques for creating secure point-to-point 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).

=== Overview===
OpenVPN Access Server is a full featured secure network tunneling VPN software solution that integrates OpenVPN server capabilities, enterprise management capabilities, simplified OpenVPN Connect UI, and OpenVPN Client software packages that accommodate Windows, MAC, Linux, Android, and iOS environments. OpenVPN Access Server supports a wide range of configurations, including secure and granular remote access to internal network and/ or private cloud network resources and applications with fine-grained access control.
=== Supported Operation Systems===
OpenVPN currently supports all main operation systems such as Windows, Mac OS X, Android, iOS and Linux It is possible to download software for your machine on the official website or it is possible to get it after installation of Access Server and logging in with your credentials to your ip_address_or_domain_name:943 (port 943 is default can be changed in the config) and it is possible to download after logging in connection profile for autologin or user-locked profile. (possible to change those settings in the Admin panel of OpenVPN Access Server.
=== Pricing===
OpenVPN is a free sorfware application which provides you 2 user license ( which means that 2 users/machines can be using current OpenVPN Access Server at the same time) after installation which is more then enough for a one person to use. Although it is possible to purchase more Licenses on official website for 9.60$ per concurrent user. And minimum license term is for one year.
== Operating system to Host Access Server software==
Currently, the Access Server software must be run on a 32-bit or 64-bit Linux host. The software is released in the form of binary package files for particular Linux distributions. Supported are RedHat, Fedora, CentOS, Ubuntu, Debian and openSUSE (Most RPM packages can be ran on the following systems: CentOS 6 and 7, Fedora 22, RHEL 6, openSUSE 13. The Deb packages can be ran on the following systems: Ubuntu 12, Debian 6,7,8)

== Difference between Community Edition VPN and Access Server==
Both Community Edition and Access Server is provided by OpenVPN and they both have something in common like: Secured VPN Tunnel, GUI Client, Bridging, Configurable Ciphers and Real-time compression. But Access Server provides more options such as Web Based GUI (it is possible to use VPN without need of downloading any additional software), Pre-configured Client (possible to download auto filled profile and Auto-login option available), Automated Certificate Creation (Access server web page will also be protected with encrypted https connection (TLS 1.2, The connection is encrypted and authenticated using AES_128_GCM and uses ECDHE_RSA as the key exchange mechanism.) Easy Deployment, Failover Solution, Simple User Management, Pre-built Virtual Appliances, Fill LDAP support, Easy Scalability, User-mode Client, Multi-daemon mode and DMZ mode.
== Step by Step Installation and configuration tutorial on Ubuntu Linux host machine==
Prerequisites: Ubuntu Linux machine and some Linux beginner skills.
The installation of OpenVPN-AS is simple. In this tutorial I will be using Ubuntu 14.04 64-bit VPS server.

'''1)''' First we would need to become root

''Command:'' <code> sudo su</code>

'''2)''' We would need to download the latest software installation files from official website which can be found here: [https://openvpn.net/index.php/access-server/download-openvpn-as-sw.html Official Download Page] (Click on the needed Operation System and select needed version to download (32 bit or 64 bit and Ubuntu version 12 or 14) then right click on it and copy link)

'''3)''' Now we go back to our console panel and download the OpenVPN Access Server using wget and paste copied link before. File will be downloaded by default to root user home directory. (it is possible to change.) File will be something around 28 MB (my file 64bit Ubuntu Linux)

''Command:'' <code>wget http://swupdate.openvpn.org/as/openvpn-as-2.0.25-Ubuntu12.amd_64.deb </code>

'''4)''' Now we install downloaded file using following command dpkg –i (And downloaded file name)

''Command:'' <code>dpkg –i openvpn-as-2.0.25-Ubuntu12.amd_64.deb</code>

That’s it. OpenVPN AS is now installed. But there is some configurations needed before we can use it.

'''5)''' During the installation OpenVPN created admin user which is by default called “openvpn” but the password left empty for security reasons are are going to change the password using command (as root) after command you will be provided with be promted to enter password. Make sure your password is secure!

''Command:'' <code>passwd openvpn</code>

'''6)''' Now we are going to check the OpenVPN AS web interface which can be found by default port 943 and your ip address, login using username openvpn and password what you set before. (After logging in you would need to click Agree to accept the License Agreement.

Admin page: https://ip_address_or_domain:943/admin
Client page: https://ip_address_or_domain:943/

Note: The server’s SSL is self-signed so not need to worry about the bad security warning

'''7)''' Download needed OpenVPN Connect software by clicking the link. After it has finished downloading, run it and enter your credentials. And connection to your Access Server have been established. You can also download official Android or iOS application to use VPN on your smartphone.
Note: You can also login to Admin Ul page if you want to add users or change settings, although the default settings works fine without any problems.

We are done! Have fun with your OpenVPN Access Server for free and be more secure using this encrypted connection.

Tutorial created by Artur Ovtsinnikov, if you have any questions it is possible to contact me by email.

== See Also==
A bit better Step-by-Step pdf tutorial with screenshots can be downloaded here: LINK

==References==
https://openvpn.net

https://openvpn.net/index.php/access-server/overview.html

https://openvpn.net/index.php/access-server/docs/admin-guides-sp-859543150.html

https://en.wikipedia.org/wiki/OpenVPN

https://en.wikipedia.org/wiki/Pre-shared_key

File:Openvpn2.png

2016-04-03T14:47:56Z

Aovtsinn: