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howtos:network_services:openvpn [2013/05/19 19:10 (UTC)]
chrisabela
howtos:network_services:openvpn [2018/04/06 21:19 (UTC)] (current)
chrisabela Updated for Slackware 14.2
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 +
 ====== OpenVPN - How to Set Up a Slackware Server and a Slackware Client ====== ====== OpenVPN - How to Set Up a Slackware Server and a Slackware Client ======
  
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 ===== 2. Scope and Objective ===== ===== 2. Scope and Objective =====
  
-The objective of this how-to ​is to serve as a tutorial for the readers to set up a basic but functional Slackware VPN Server and Client over the Internet.+The objective of this article ​is to serve as a tutorial for the readers to set up a basic but functional Slackware VPN Server and Client over the Internet.
  
-The emphasis ​of this tutorial ​is to provide ​you with a reliable method that you can easily ​follow ​to setup OpenVPN on Slackware Servers and Clients. Nevertheless the process is still not free from pitfalls and require some attention and determination ​to set up.+The emphasis is to provide a reliable method that can be easily ​followed ​to set-up ​OpenVPN on Slackware Servers and Clients. Nevertheless the process is still not free from pitfalls and require some attention and determination.
  
-This document ​comprises of a selection of other similar tutorials found on the Internet. In  particular the methods described here were extracted from References ​(2) and (3). However these were cutomised ​to satisfy the objective. ​+This article ​comprises of a selection of other similar tutorials found on the Internet ​particularly ​(2) and (3) and the documents contained in the downloaded source files. However these are reformatted ​to satisfy the objective. ​
  
 ===== 3. Installation ===== ===== 3. Installation =====
  
-Openvpn is already installed on Slackware if a default installation was followed. If this was not the case, then it is available from the "​n"​ directory of the Slackware DVD. Refer to other Slackware specific documents on how to go about this installation.+Openvpn is already installed on Slackware if a default installation was followed. If this was not the case, then the package ​is available from the "​n"​ directory of the Slackware DVD. Refer to other Slackware specific documents on how to go about this installation.
  
 If you want to confirm that Openvpn is indeed installed, you can check it by listing the /​var/​log/​packages/​ directory: If you want to confirm that Openvpn is indeed installed, you can check it by listing the /​var/​log/​packages/​ directory:
Line 25: Line 26:
 <​code>​ <​code>​
 # ls /​var/​log/​packages/​openvpn* # ls /​var/​log/​packages/​openvpn*
-/​var/​log/​packages/​openvpn-2.2.2-i486-1 
 </​code>​ </​code>​
  
 ===== 4. Requirements ===== ===== 4. Requirements =====
  
-Server and a Client computers would be needed. They would have to be connected to the Internet on two different Routers and different Network Routes. ​ For the purpose of this tutorial, specific details are defined in order to enhance the readability. Of course, you will probably have a different addresses, so you will need to amend accordingly.+Server and a Client computers would be needed. They would have to be connected to the Internet on two different Routers and different Network Routes. ​ For the purpose of this tutorial, specific details are defined in order to enhance the readability. Of course, you will probably have a different addresses, so you will need to amend accordingly.
  
 ==== 4.1. Server DNS ==== ==== 4.1. Server DNS ====
  
-A URL is normally used to address the Server. This is not mandatory and instead you may use only the Internet IP. However ​I recommend using a URL for the Server, especially if it is connected to a dynamic IP, which is typical for domestic Internet connections. The author is using noip2(4) as it is free upon subscription. ​Noip2 is available from http://​slackbuilds.org.+A URL is normally used to address the Server. This is not mandatory and instead you may use only the Internet IP. However ​it is recommended to use a URL to access ​the Server ​from the Internet, especially if it is connected to a dynamic IP, which is typical for domestic Internet connections. The author is using noip2(4) as it is free upon subscription. ​A noip2 slackbuild ​is available from http://​slackbuilds.org.
  
 ==== 4.2. Server details ==== ==== 4.2. Server details ====
Line 40: Line 40:
 <​code>​ <​code>​
 hostname: server1 hostname: server1
-IP: 192.168.200.199/​255.255.255.0+IP: 192.168.200.195/​255.255.255.0
 URL:  servervpn.no-ip.org URL:  servervpn.no-ip.org
 Network Interface: eth0 Network Interface: eth0
Line 49: Line 49:
 <​code>​ <​code>​
 hostname: client1 hostname: client1
-IP: 192.168.1.234/​255.255.255.0+IP: 192.168.1.101/​255.255.255.0
 Network Interface: wlan0 Network Interface: wlan0
 </​code>​ </​code>​
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 ==== 4.3 Administrator Rights ==== ==== 4.3 Administrator Rights ====
  
-You will need to have administrator rights to set up the Openvpn. This applies to both the Server and the Client. ​In this tutorial, it will be assumed that all actions will be performed by the root user.+You will need to have administrator rights to set up OpenVPN. This applies to both the Server and the Client. ​For simplicity, in this tutorial, it will be assumed that all actions will be performed by the root user. Naturally advanced users might be more discerning.
  
 ==== 4.4 Possible Constraints and Possible Solutions for a WiFi equipped Client ==== ==== 4.4 Possible Constraints and Possible Solutions for a WiFi equipped Client ====
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 ===== 5. Creating a Public Key Infrastructure (PKI) using the easy-rsa Scripts ===== ===== 5. Creating a Public Key Infrastructure (PKI) using the easy-rsa Scripts =====
  
-The PKI may be created on any computer with an Openvpn ​installation,​ but it is probably more sensible to be done on the Server. In any case, in this tutorial ​it will be assumed that this is the case. +The PKI may be created on any computer with a VPN installation,​ but it is probably more sensible to be done on both the Server ​and the Client as both would need it. An easy way to build the PKI is to use the easy-rsa ​scriptsThese may be downloaded like this:
- +
-The easy-rsa scripts referred ​to in this chapter reside in the /usr/doc/ directory. +
- +
-It is not recommended ​to use this directory to create ​the PKI. This directory may be overwritten by an Openvpn package upgrade, and some files that will be created, should kept secret as otherwise the security of the created VPN would be compromised. +
- +
-Copy the whole easy-rsa ​directory to root's home directory.+
  
 <​code>​ <​code>​
-cp -r /usr/doc/​openvpn-2.2.2/easy-rsa /root  +cd 
-# cd /root/easy-rsa/2.0/+# git clone http://github.com/OpenVPN/easy-rsa
 </​code>​ </​code>​
  
-Find the vars file. As a minimum ​it is recommended to edit the following:+and then archive ​it for future purposes:
  
 <​code>​ <​code>​
-KEY_COUNTRY +# tar cvf easy-rsa.tar easy-rsa
-KEY_PROVINCE +
-KEY_ORG +
-KEY_EMAIL+
 </​code>​ </​code>​
  
-The purpose of this recommendation is to assure consistency in the default values of some following steps that need to be followedYou should not be really worried about the exact meaning or the correctness of the chosen entries as the actual values will have no bearing on the success or failure of this exercise.+==== 5.1 Create ​the keys and certificates for the Server ====
  
-The following is my complete vars file. You may note some additional entries that were entered. Most of these are meant to enhance the range of default values that will be immediately available, thus increasing the chances of a successful creation of the PKI.+Follow ​these steps on the Server ​to create ​the needed keys and certificates:​
  
 <​code>​ <​code>​
-# easy-rsa ​parameter settings  +cd easy-rsa/easyrsa3
- +
-# NOTE: If you installed from an RPM,  +
-# don't edit this file in place in  +
-/usr/​share/​openvpn/​easy-rsa --  +
-# instead, you should copy the whole  +
-# easy-rsa directory to another location  +
-# (such as /​etc/​openvpn) so that your  +
-# edits will not be wiped out by a future  +
-# OpenVPN package upgrade.  +
- +
-# This variable should point to  +
-# the top level of the easy-rsa  +
-# tree.  +
-export EASY_RSA="​`pwd`"​  +
- +
-#  +
-# This variable should point to  +
-# the requested executables  +
-#  +
-export OPENSSL="​openssl"​  +
-export PKCS11TOOL="​pkcs11-tool"​  +
-export GREP="​grep"​  +
- +
- +
-# This variable should point to  +
-# the openssl.cnf file included  +
-# with easy-rsa.  +
-export KEY_CONFIG=`$EASY_RSA/​whichopensslcnf $EASY_RSA`  +
- +
-# Edit this variable to point to  +
-# your soon-to-be-created key  +
-# directory.  +
-#  +
-# WARNING: clean-all will do  +
-# a rm -rf on this directory  +
-# so make sure you define  +
-# it correctly!  +
-export KEY_DIR="​$EASY_RSA/​keys"​  +
- +
-# Issue rm -rf warning  +
-echo NOTE: If you run ./​clean-all,​ I will be doing a rm -rf on $KEY_DIR  +
- +
-# PKCS11 fixes  +
-export PKCS11_MODULE_PATH="​dummy"​  +
-export PKCS11_PIN="​dummy"​  +
- +
-# Increase this to 2048 if you  +
-# are paranoid. ​ This will slow  +
-# down TLS negotiation performance  +
-# as well as the one-time DH parms  +
-# generation process.  +
-export KEY_SIZE=2048  +
- +
-# In how many days should the root CA key expire?  +
-export CA_EXPIRE=3650  +
- +
-# In how many days should certificates expire?  +
-export KEY_EXPIRE=3650  +
- +
-# These are the default values for fields  +
-# which will be placed in the certificate.  +
-# Don't leave any of these fields blank.  +
-export KEY_COUNTRY="​MT"​  +
-export KEY_PROVINCE="​Malta"​  +
-export KEY_CITY="​Valletta"​  +
-export KEY_ORG="​ABCDEF Co. Ltd."  +
-#export KEY_EMAIL="​me@myhost.mydomain"​  +
-export KEY_EMAIL=support@abcdef.com  +
-export KEY_CN=server1  +
-export KEY_NAME=server1  +
-export KEY_OU=""​  +
-export PKCS11_MODULE_PATH=changeme  +
-export PKCS11_PIN=1234 ​+
 </​code>​ </​code>​
  
-Source ​the vars file:+Create ​the PKI and the CA:
  
 <​code>​ <​code>​
-source ​./vars +# ./easyrsa init-pki 
-NOTE: If you run ./clean-all, I will be doing a rm -rf on /​root/​easy-rsa/​2.0/​keys+./easyrsa build-ca
 </​code>​ </​code>​
  
-Proceed like this:+Enter a PEM pass phrase, reverify it and then enter a name for the server. In this article I am using the hostnames for clarity (in this case: server1), but you may choose any name. 
 + 
 +Then generate the request:
  
 <​code>​ <​code>​
-# ./clean-all +# ./easyrsa gen-req server1
-# ./​build-ca +
-Generating a 2048 bit RSA private key  +
-.....................+++  +
-.......................................................................+++  +
-writing new private key to '​ca.key'​  +
------  +
-You are about to be asked to enter information that will be incorporated  +
-into your certificate request.  +
-What you are about to enter is what is called a Distinguished Name or a DN.  +
-There are quite a few fields but you can leave some blank  +
-For some fields there will be a default value,  +
-If you enter '​.',​ the field will be left blank.  +
------  +
-Country Name (2 letter code) [MT]:  +
-State or Province Name (full name) [Malta]:  +
-Locality Name (eg, city) [Valletta]:  +
-Organization Name (eg, company) [ABCDEF Co. Ltd.]:  +
-Organizational Unit Name (eg, section) []:  +
-Common Name (eg, your name or your server'​s hostname) [server1]:  +
-Name [server1]:  +
-Email Address [support@abcdef.com]: ​+
 </​code>​ </​code>​
  
-**Hint: The less information you enter, the less likely it will cause you problems later on.**+You will be prompted for another PEM pass phrase to reverify it and to confirm that the name of the entity is indeed server1Now you may proceed to sign this request:
  
 <​code>​ <​code>​
-# ./build-key-server server1+# ./easyrsa sign-req server server1
 </​code>​ </​code>​
  
-**Do not enter a challenge password or company name when prompted.**+Confirm the request by entering "​yes",​ then enter the original ca PEM passphrase. 
 + 
 +Now create two additional key files:
  
 <​code>​ <​code>​
-Generating a 2048 bit RSA private key  +# cd /​etc/​openvpn/​certs/​ 
-........................+++ ​ +# openssl dhparam -out dh2048.pem 2048 
-................................................+++  +# cd /​etc/​openvpn/​keys/​ 
-writing new private key to '​server1.key' ​ +# /​usr/​sbin/​openvpn ​--genkey ​--secret ta.key  
------  +</code>
-You are about to be asked to enter information that will be incorporated  +
-into your certificate request.  +
-What you are about to enter is what is called a Distinguished Name or a DN.  +
-There are quite a few fields but you can leave some blank  +
-For some fields there will be a default value,  +
-If you enter '​.',​ the field will be left blank.  +
------  +
-Country Name (2 letter ​code) [MT]:  +
-State or Province Name (full name) [Malta]:  +
-Locality Name (eg, city) [Valletta]:  +
-Organization Name (eg, company) [ABCDEF Co. Ltd.]:  +
-Organizational Unit Name (eg, section) []:  +
-Common Name (eg, your name or your server'​s hostname) [server1]:  +
-Name [server1]:  +
-Email Address [support@abcdef.com]: ​+
  
-Please enter the following '​extra'​ attributes  +==== 5.Create ​the keys and certificates for the Client ====
-to be sent with your certificate request  +
-A challenge password []:  +
-An optional company name []:  +
-Using configuration from /​root/​easy-rsa/​2.0/​openssl-1.0.0.cnf  +
-Check that the request matches the signature  +
-Signature ok  +
-The Subject'​s Distinguished Name is as follows  +
-countryName ​          :​PRINTABLE:'​MT'​  +
-stateOrProvinceName ​  :​PRINTABLE:'​Malta'​  +
-localityName ​         :​PRINTABLE:'​Valletta'​  +
-organizationName ​     :​PRINTABLE:'​ABCDEF Co. Ltd.'  +
-commonName ​           :​PRINTABLE:'​server1'​  +
-name                  :​PRINTABLE:'​server1'​  +
-emailAddress ​         :​IA5STRING:'​support@abcdef.com'​  +
-Certificate is to be certified until Jan 18 19:37:43 2023 GMT (3650 days)  +
-Sign the certificate?​ [y/​n]:​y ​+
  
 +Follow these steps on the Client to create the needed keys and certificates:​
  
-1 out of 1 certificate requests certifiedcommit? [y/n]y  +You will need the easy-rsa scriptsso you can copy the easy-rsa tarball from the Server to the Client and extract it:
-Write out database with 1 new entries  +
-Data Base Updated  +
-</​code>​+
  
 <​code>​ <​code>​
-./build-dh +cd 
-This is going to take a long time  +# tar xvf easy-rsa.tar
-..................+...........................................................................................................  +
-.................................................................+
 </​code>​ </​code>​
 +
 +Now create the PKI and generate the request:
  
 <​code>​ <​code>​
-# ./build-key client1+# cd easy-rsa/​easyrsa3 
 +# ./easyrsa init-pki 
 +# ./easyrsa gen-req client1
 </​code>​ </​code>​
  
-** Do not enter a challenge password or company name when prompted.**+You will be prompted ​for another PEM pass phrase, to re-verify it and to confirm that the name of the entity is indeed client1. In this article I am using the hostnames for clarity (in this case: client1), but you may choose any name.
  
-<​code>​ +Copy pki/reqs/client1.req back to the Server.
-Generating a 2048 bit RSA private key  +
-...............................................................................................+++  +
-..+++  +
-writing new private key to 'client1.key'  +
------  +
-You are about to be asked to enter information that will be incorporated  +
-into your certificate request.  +
-What you are about to enter is what is called a Distinguished Name or a DN.  +
-There are quite a few fields but you can leave some blank  +
-For some fields there will be a default value,  +
-If you enter '​.', ​the field will be left blank.  +
------  +
-Country Name (2 letter code) [MT]:  +
-State or Province Name (full name) [Malta]:  +
-Locality Name (eg, city) [Valletta]:  +
-Organization Name (eg, company) [ABCDEF Co. Ltd.]:  +
-Organizational Unit Name (eg, section) []:  +
-Common Name (eg, your name or your server'​s hostname) [client1]:  +
-Name [server1]:  +
-Email Address [support@abcdef.com]: +
  
-Please enter the following '​extra'​ attributes  +=== 5.2.1 Sign the Client'​s ​request on the Server ===
-to be sent with your certificate request  +
-A challenge password []:  +
-An optional company name []:  +
-Using configuration from /​root/​easy-rsa/​2.0/openssl-1.0.0.cnf  +
-Check that the request matches the signature  +
-Signature ok  +
-The Subject'​s ​Distinguished Name is as follows  +
-countryName ​          :​PRINTABLE:'​MT'​  +
-stateOrProvinceName ​  :​PRINTABLE:'​Malta'​  +
-localityName ​         :​PRINTABLE:'​Valletta'​  +
-organizationName ​     :​PRINTABLE:'​ABCDEF Co. Ltd.'  +
-commonName ​           :​PRINTABLE:'​client1'​  +
-name                  :​PRINTABLE:'​server1'​  +
-emailAddress ​         :​IA5STRING:'​support@abcdef.com'​  +
-Certificate is to be certified until Jan 18 19:42:33 2023 GMT (3650 days)  +
-Sign the certificate?​ [y/​n]:​y ​+
  
- +For the purpose ​of this articleit is assumed that the Client'​s request file (client1.req) has been transferred to the $HOME/openvpndirectory of the Server. Now you can proceed to import and sign the client1 request:
-1 out of 1 certificate requests certifiedcommit? [y/n]y  +
-Write out database with 1 new entries  +
-Data Base Updated  +
-</code>+
  
 <​code>​ <​code>​
-openvpn --genkey --secret /root/easy-rsa/2.0/keys/ta.key+cd $HOME/easy-rsa/easyrsa3 
 +./easyrsa import-req $HOME/openvpn/​client1.req client1 
 +# ./easyrsa sign-req client client1
 </​code>​ </​code>​
 +
 +When prompted enter "​yes"​ and the server1 CA PEM pass phrase. ​
 +
 +Copy the generated $HOME/​easy-rsa/​easyrsa3/​pki/​issued/​client1.crt
 +back to the client.
  
 ===== 6. Setting up the Server ===== ===== 6. Setting up the Server =====
Line 326: Line 163:
  
 <​code>​ <​code>​
-# cp /root/easy-rsa/2.0/keys/{ca.crt,server1.crt,​dh2048.pem} ​\+# cp $HOME/easy-rsa/easyrsa3/pki/​ca.crt ​
 +> /​etc/​openvpn/​certs/​ 
 +# cp $HOME/​easy-rsa/​easyrsa3/​pki/​issued/​server1.crt \
 > /​etc/​openvpn/​certs/​ > /​etc/​openvpn/​certs/​
-# cp /root/easy-rsa/2.0/keys/{server1.key,​ta.key} ​\+# cp $HOME/easy-rsa/easyrsa3/pki/private/​server1.key \
 > /​etc/​openvpn/​keys/​ > /​etc/​openvpn/​keys/​
 </​code>​ </​code>​
  
-Restrict ​the permission ​of /etc/openvpn/keys/+Copy the sample server.conf from the OpenVPN source onto the OpenVPN'​s configuration directory. The source ​of OpenVPN may be obtained from Slackware'​s source DVD or your favourite Slackware mirror or from http://openvpn.net. In the following example, I am downloading the source from ftp.slackware.com
  
 <​code>​ <​code>​
-chmod 700 /etc/openvpn/keys+cd /tmp/ 
 +# wget -c \ 
 +> ftp://​ftp.slackware.com/​pub/​slackware/​slackware/​source/​n/openvpn/openvpn-*.tar.?​z 
 +# cd /usr/src/ 
 +# tar xvf /​tmp/​openvpn-*.tar.?​z
 </​code>​ </​code>​
  
-On the Server machine copy the sample ​server.conf ​onto the openvpn'​s ​configuration directory.+Copy the file server.conf ​contained in the source to the OpenVPN ​configuration directory:
  
 <​code>​ <​code>​
-# cp /usr/doc/openvpn-2.2.2/​sample-config-files/​server.conf \+# cp openvpn-*/sample/​sample-config-files/​server.conf \
 > /​etc/​openvpn/​ > /​etc/​openvpn/​
 </​code>​ </​code>​
Line 360: Line 203:
 ;user nobody ​ ;user nobody ​
 ;group nobody ;group nobody
 +
 +;​log-append ​ openvpn.log
 </​code>​ </​code>​
  
-To+To:
  
 <​code>​ <​code>​
Line 375: Line 220:
 user nobody ​ user nobody ​
 group nobody group nobody
 +
 +log-append ​ /​var/​log/​openvpn.log
 </​code>​ </​code>​
  
-**Note** that comments in server.conf ​may be either start with # or ; In order to help you with entering parameters, the former are used to comment out text while the latter are for commented out configuration lines.+Finally add the following to /​etc/​openvpn/​server.conf:
  
-Copy the rc.openvpn-server ​listed hereunder and place under /etc/rc.d/+<​code>​ 
 +# Select a cryptographic cipher. 
 +# This config item must be copied to 
 +# the client config file as well. 
 +cipher AES-256-CBC 
 +# If you want to use OpenVPN as a daemon, uncomment this line. 
 +# Generally speaking, servers should run OpenVPN as a daemon 
 +;daemon 
 +</​code>​ 
 + 
 +<​note>​An attentive reader may be tempted to uncomment the '​daemon'​ option. This would not allow the user to enter the pass phrase, therefore it would not work until the pass phrase is defined in server.conf as described in Chapter 10.</​note>​ 
 + 
 +<​code>​ 
 +# cat /​var/​log/​openvpn.log 
 +</​code>​ 
 + 
 +<​note>​Note that comments in server.conf may be either start with # or ; In order to help you with entering parameters, the former are used to comment out text while the latter are for commented out configuration lines.</​note>​ 
 + 
 +Copy the rc.openvpn listed hereunder and place under /etc/rc.d/
  
 <​code>​ <​code>​
 #​!/​bin/​sh ​ #​!/​bin/​sh ​
  
-# /​etc/​rc.d/​rc.openvpn-server ​+# /​etc/​rc.d/​rc.openvpn ​
  
-# Start/​stop/​restart the openvpn ​server. ​ +# Start/​stop/​restart the OpenVPN ​server.  
-#  +
-# To make OpenVPN start automatically at boot, make this  + 
-# file executable: ​ chmod 755 /​etc/​rc.d/​rc.openvpn-server ​ +
-#  +
 ovpn_start() {  ovpn_start() { 
   if [ -x /​usr/​sbin/​openvpn -a -r /​etc/​openvpn/​server.conf ]; then    if [ -x /​usr/​sbin/​openvpn -a -r /​etc/​openvpn/​server.conf ]; then 
     echo "​Starting OpenVPN: ​ /​usr/​sbin/​openvpn server.conf" ​     echo "​Starting OpenVPN: ​ /​usr/​sbin/​openvpn server.conf" ​
-    /​usr/​sbin/​openvpn /​etc/​openvpn/​server.conf ​+    /​usr/​sbin/​openvpn /​etc/​openvpn/​server.conf
   fi    fi 
  
Line 427: Line 289:
  
 <​code>​ <​code>​
-# chmod 755 /​etc/​rc.d/​rc.openvpn-server+# chmod 755 /​etc/​rc.d/​rc.openvpn
 </​code>​ </​code>​
  
 ===== 7. Port Forwarding ===== ===== 7. Port Forwarding =====
  
-You will need to forward traffic from the port you have chosen for Openvpn ​to be routed to the Server. To accomplish this you will need to provide your Server with a fixed IP and you will need to configure your router. You may use netconfig, ​wicd or network-manager to set the fixed IP on Slackware. Then you also need to consult the documentation provided with your router to set up the selected IP address reserved for the Server, and the port forwarding. For our default ​Openvpn ​set up, the UDP Port would be 1194. +You will need to forward traffic from the port you have chosen for OpenVPN ​to be routed to the Server. To accomplish this you will need to provide your Server with a fixed IP and you will need to configure your router. You may use netconfig, network-manager ​or wicd to set the fixed IP on Slackware. Then you also need to consult the documentation provided with your router to set up the selected IP address reserved for the Server, and the port forwarding. For our default ​OpenVPN ​set up, the UDP Port would be 1194. 
  
-In case if you have misplaced such documentation,​ you may search on the Internet on how this may be achieved. A good place to start is http://​portforward.com/​. Astute readers are warned that typical port scanning tools like nmap might not be able to detect your open ports at this stage.+In case if you have misplaced such documentation,​ you may search on the Internet on how this may be achieved. A good place to start is http://​portforward.com/​.
  
 ===== 8. Setting up the Client ===== ===== 8. Setting up the Client =====
  
-On the client ​machine perform the following instructions to set it up.+On the Client ​machine perform the following instructions to set it up. 
 + 
 +Download the OpenVPN source tarball and extracted it as explained in Chapter 6, then proceed to copy the included configuration file for clients:
  
 <​code>​ <​code>​
-# cp /usr/doc/openvpn-2.2.2/​sample-config-files/​client.conf \+# cp /usr/src/openvpn-*/sample/​sample-config-files/​client.conf \
 > /​etc/​openvpn/​ > /​etc/​openvpn/​
 </​code>​ </​code>​
Line 475: Line 339:
 </​code>​ </​code>​
  
-**Note** that comments in client.conf ​may be either # or ; The former are used to comment out text while the latter are for commented out configuration lines. This should help you a lot in the configuration process. +Finally add the following to /​etc/​openvpn/​client.conf:​
- +
-You will need the following files that were generated by the easy-rsa scripts:+
  
 <​code>​ <​code>​
-ca.crt +# Select a cryptographic cipher
-client1.crt +# This config item must be copied to 
-client1.key +# the server config file as well
-ta.key+cipher AES-256-CBC
 </​code>​ </​code>​
  
-Place these files as indicated ​in client.conf. So ca.crt and client1.crt go under /​etc/​openvpn/​certs/ ​while client1.key and ta.key go under /​etc/​openvpn/​keys/+<​note>​Note that comments ​in client.conf ​may be either # or ; The former are used to comment out text while the latter are for commented out configuration linesThis should help you a lot in the configuration process.</note>
  
-Copy the following rc.openvpn-client listed hereunder and place under /etc/rc.d/+You will need this file that was generated by the Client'​s easy-rsa scripts:
  
 <​code>​ <​code>​
-#!/bin/sh  +cp $HOME/easy-rsa/easyrsa3/pki/private/client1.key \ 
-#  +/etc/openvpn/keys/ 
-/etc/rc.d/rc.openvpn-client  +</​code>​
- +
-# Start/stop/restart the openvpn ​client. ​ +
-+
  
-ovpn_start() {  +and the following from the Server'​s easy-rsa scripts:
-  if [ -x /​usr/​sbin/​openvpn -a -r /​etc/​openvpn/​client.conf ]; then  +
-    echo "​Starting OpenVPN /​usr/​sbin/​openvpn client.conf"​  +
-    /​usr/​sbin/​openvpn /​etc/​openvpn/​client.conf &  +
-  fi  +
-+
  
-ovpn_stop() {  +<​code>​ 
-  ​killall openvpn  +$HOME/​easy-rsa/​easyrsa3/​pki/​ca.crt 
-}  +$HOME/​easy-rsa/​easyrsa3/​pki/​issued/​client1.crt
- +
-ovpn_restart() {  +
-  ovpn_stop  +
-  sleep 2  +
-  ovpn_start  +
-}  +
-  +
-case "$1" in  +
-'​start'​)  +
-  ovpn_start  +
-  ;;  +
-'​stop'​)  +
-  ovpn_stop  +
-  ;;  +
-'​restart'​)  +
-  ovpn_restart  +
-  ;;  +
-*)  +
-  echo "​Usage: ​$0 {start|stop|restart}"​  +
-esac+
 </​code>​ </​code>​
  
-Then give it executable permissions:+and this file as well:
  
 <​code>​ <​code>​
-# chmod +x /etc/rc.d/rc.openvpn-client+/etc/openvpn/keys/ta.key
 </​code>​ </​code>​
 +
 +Place these files as indicated in client.conf. So ca.crt and client1.crt go under /​etc/​openvpn/​certs/​ while client1.key and ta.key go under /​etc/​openvpn/​keys/​
  
 ===== 9. Testing the VPN ===== ===== 9. Testing the VPN =====
Line 541: Line 377:
  
 <​code>​ <​code>​
-# /​etc/​rc.d/​rc.openvpn-server ​start+# /​etc/​rc.d/​rc.openvpn start
 </​code>​ </​code>​
 +
 +Enter the Server PEM pass phrase when prompted.
  
 On the Client: On the Client:
  
 <​code>​ <​code>​
-# /etc/rc.d/rc.openvpn-client ​start+# /usr/sbin/​openvpn ​/​etc/​openvpn/​client.conf
 </​code>​ </​code>​
 +
 +Enter the Client PEM pass phrase when prompted. To stop OpenVPN on the Client just hit CTRL+C
  
 On both you should see a new network interface called tun0. On the Server, I obtained the following: On both you should see a new network interface called tun0. On the Server, I obtained the following:
Line 592: Line 432:
 </​code>​ </​code>​
  
-To start the openvpn ​service ​automatically ​on boot-up from the Serverinclude these lines in /​etc/​rc.d/​rc.local+===== 10. Storing the PEM pass phrase in a secure file and Automatic start of service after booting ===== 
 + 
 +To start the OpenVPN ​service on boot, an entry in /​etc/​rc.d/​rc.local ​is needed, but you would have to enter the server PEM pass phrase every time. This might be undesirable if the Server is unreachable. If this is the case, create a file containing your PEM pass phrase in a secure location; e.g. /​root/​password.ovpn which contains only this pass phrase. Then restrict its permission:
  
 <​code>​ <​code>​
-Start the OpenVPN Server +chmod 600 /​root/​password.ovpn 
-if [ -x /​etc/​rc.d/​rc.openvpn-server ​]; then  +</​code>​ 
-  /​etc/​rc.d/​rc.openvpn-server ​start + 
 +On the Server, edit /​etc/​openvpn/​server.conf with the following lines: 
 + 
 +<​code>​ 
 +askpass /​root/​password.ovpn 
 +auth-nocache 
 +</​code>​ 
 + 
 +Also, uncomment the '​daemon'​ option. 
 + 
 +This may be repeated also on the Client, just edit /​etc/​openvpn/​client.conf instead of /​etc/​openvpn/​server.conf. 
 + 
 +To start the OpenVPN ​service automatically on boot-up from the Server, include these lines in /​etc/​rc.d/​rc.local 
 + 
 +<​code>​ 
 +# Start the OpenVPN Service 
 +if [ -x /​etc/​rc.d/​rc.openvpn ]; then  
 +  /​etc/​rc.d/​rc.openvpn start 
 fi fi
 </​code>​ </​code>​
  
-===== 10. IP Routing =====+An alternate method (albeit less secure) is to remove the passphrase from server1.key file altogether. ​ Don't forget to set permissions on the key to avoid it being world-readable. 
 + 
 +<​code>​ 
 +# cd /​etc/​openvpn/​keys 
 +# openssl rsa -in server1.key -out tmp.key 
 +# mv tmp.key server1.key 
 +# chmod 600 server1.key 
 +</​code>​ 
 + 
 + 
 +===== 11. IP Routing =====
  
 Up to now we have created a tunnel device on both the Server and the Client called tun0 which is visible only to these two machines. However more work is needed to route the Client'​s connection via tun0 and then to the WAN that is connected to the Server. Up to now we have created a tunnel device on both the Server and the Client called tun0 which is visible only to these two machines. However more work is needed to route the Client'​s connection via tun0 and then to the WAN that is connected to the Server.
  
-==== 10.1 Server Configuration ====+==== 11.1 Server Configuration ====
  
 Enable IP forwarding: Enable IP forwarding:
Line 635: Line 504:
 push "route 192.168.200.0 255.255.255.0"​ push "route 192.168.200.0 255.255.255.0"​
  
-client-config-dir ccd +client-config-dir ​/​etc/​openvpn/​ccd 
 route 192.168.1.0 255.255.255.0 ​ route 192.168.1.0 255.255.255.0 ​
  
Line 645: Line 514:
  
 Naturally replace 192.168.200.0 255.255.255.0 with the Server'​s Network Route, and  192.168.1.0 255.255.255.0 with the Client'​s Network Route. Naturally replace 192.168.200.0 255.255.255.0 with the Server'​s Network Route, and  192.168.1.0 255.255.255.0 with the Client'​s Network Route.
 +208.67.222.222 and 208.67.220.220 are the OpenDNS IP addresses.
 +
 +<note warning>​Up to now the DNS push configuration has not been successful.</​note>​
 +
 +You can either use the original Client DNS servers or else you may rewrite /​etc/​resolv.conf manually:
 +
 +<​code>​
 +# OpenDNS Servers
 +nameserver 208.67.222.222
 +nameserver 208.67.220.220
 +</​code>​
 +
 +According to your routing table however, it is still worth trying to use the DNS servers listed by the Client, I find that they are generally still available, so you would not need to do anything. However do be aware of possible DNS leaks if you are concerned about your privacy.
  
-208.67.222.222 and 208.67.220.220 are the OpenDNS IP addresses. Up to now the DNS push configuration has not been successful. You can either use the original ​Client DNS servers or else you may edit /​etc/​resolv.conf ​manuallyHowever it is still worth trying to use the DNS servers listed ​by the ClientI find that they are generally still be available from the Server'​s Network, so you would not need to do anything.+Some users have reported that their Client'​s Network Manager, (or any other similar application) re-wrote ​the original /​etc/​resolv.conf ​back after their manual editingThis could not be reproduced ​by the author of this article (yet)but you may consider installing and configuring openresolv(5) if this actually happens to you. A SlackBuild for openresolv may be found on http://​slackbuilds.org. Openresolv is currently out of the scope of this article.
  
 Next you will have to configure some iptables NAT forwarding on the Server (only). You can do this by first flushing the iptables: Next you will have to configure some iptables NAT forwarding on the Server (only). You can do this by first flushing the iptables:
Line 674: Line 556:
  
 <​code>​ <​code>​
-#!/bin/sh  +#!/bin/bash                                                                                                                                          ​ 
-# Start/​stop/​restart the firewall  +# Start/​stop/​restart/​status ​the firewall ​                                                                                                            ​ 
-# A VPN server iptable filter rules  +                                                                                                                                                     ​ 
-  +IPT=/​usr/​sbin/​iptables # This will provide some portability ​                                                                                          
-IPT=/​usr/​sbin/​iptables # This will provide some portability ​+                                                                                                                                                      
 +firewall_start() {                                                                                                                                    
 +                                                                                                                                                      
 +  # flush the iptables ​                                                                                                                               
 +  echo -e "​Starting the firewall ....\c" ​                                                                                                             
 +  $IPT -F                                                                                                                                             
 +                                                                                                                                                      
 +  # policies ​                                                                                                                                         
 +  $IPT -P OUTPUT DROP                                                                                                                                 
 +  $IPT -P INPUT DROP                                                                                                                                  
 +  $IPT -P FORWARD DROP 
  
-firewall_start() { +  $IPT -N SERVICES # services is a custom chain 
  
-  # flush the iptables ​ +  # allowed output 
-  $IPT -F  +  $IPT -A OUTPUT -o lo -j ACCEPT 
- +  $IPT -OUTPUT ​-o eth0 -j ACCEPT 
-  # policies ​ +  $IPT -A OUTPUT ​-o tun0 -j ACCEPT
-  $IPT -OUTPUT ACCEPT  +
-  $IPT -P INPUT DROP  +
-  $IPT -P FORWARD DROP  +
-  $IPT -N SERVICES # services is a custom chain +
  
   # allowed inputs ​   # allowed inputs ​
-  #$IPT -A INPUT -i lo -j ACCEPT # Uncomment ​if the Server ​is a desktop  +  #$IPT -A INPUT -i lo -j ACCEPT # uncomment ​if the host is a desktop ​ 
-  $IPT -A INPUT -j SERVICES # Append ​the services chain to the input +  $IPT -A INPUT -m conntrack --ctstate ESTABLISHED,​RELATED -j ACCEPT # allow responses 
 +  $IPT -A INPUT -j SERVICES # append ​the services chain to the input 
  
-  # allowed ​forwards ​ +  # allowed ​forwarding for OpenVPN 
-  $IPT -A FORWARD -i eth0 -o tun0 -m state --state ESTABLISHED,​RELATED -j ACCEPT  +  $IPT -A FORWARD -i eth0 -o tun0 -m state --state ESTABLISHED,​RELATED -j ACCEPT 
-  $IPT -A FORWARD -s 10.8.0.0/24 -o eth0 -j ACCEPT ​+  $IPT -A FORWARD -s 10.8.0.0/24 -o eth0 -j ACCEPT
  
-  # masquerade the openvpn ​network  +  # masquerade the OpenVPN ​network 
-  $IPT -t nat -A POSTROUTING -s 10.8.0.0/24 ! -d 10.8.0.0/24 -o eth0 -j MASQUERADE ​+  $IPT -t nat -A POSTROUTING -s 10.8.0.0/24 -o eth0 -j MASQUERADE
  
-  ​# allow responses  +  # allow sshd on the default tcp port 22 
-  $IPT -A INPUT -m state --state ESTABLISHED,​RELATED -j ACCEPT  +  ​#$IPT -A SERVICES -p tcp --dport 22 -j ACCEPT ​# Uncomment to allow sshd
- +
-  # allow services  +
- +
-  # allow vpn on the default udp port 1194  +
-  $IPT -A SERVICES -p udp --dport 1194 -j ACCEPT  +
- +
-  ​# allow sshd on the default tcp port 22  +
-  $IPT -A SERVICES -p tcp --dport 22 -j ACCEPT ​+
  
 +  # allow OpenVPN for the default udp port 1194
 +  $IPT -A SERVICES -p udp --dport 1194 -j ACCEPT
 +  ​
 +  echo "​done."​
  
  
 firewall_stop() {  firewall_stop() { 
 +  echo -e "​Stopping the firewall ....\c"​
  
-  # polcies (permissive) ​+  # polcies (permissive) 
 +  $IPT -P OUTPUT ACCEPT
   $IPT -P INPUT ACCEPT ​   $IPT -P INPUT ACCEPT ​
 +  $IPT -P FORWARD ACCEPT ​
  
   # flush the iptables ​   # flush the iptables ​
Line 724: Line 612:
  
   # delete the services custom chain    # delete the services custom chain 
-  $IPT -X SERVICES  +  $IPT -X SERVICES 
-+  echo "​done."​ 
 +
 + 
 +firewall_status() { 
 +  $IPT -vL 
 +}
  
 case "​$1"​ in  case "​$1"​ in 
Line 738: Line 631:
   firewall_start ​   firewall_start ​
   ;;    ;; 
 +'​status'​)
 +  firewall_status
 +  ;;
 *)  *) 
-  echo "Usage $0 start|stop|restart" ​+  echo "Usage $0 start|stop|restart|status" ​
 esac esac
 </​code>​ </​code>​
Line 755: Line 651:
 </​code>​ </​code>​
  
-Now you will you need to do is to restart ​the OpenVPN service on the Server ​and restart the Client connection.+Restart ​the OpenVPN service on the Server:
  
-===== 11. Firewalls =====+<​code>​ 
 +# /​etc/​rc.d/​rc.openvpn restart 
 +</​code>​ 
 + 
 +and reconnect from the Client: 
 + 
 +<​code>​ 
 +# /​usr/​sbin/​openvpn /​etc/​openvpn/​client.conf 
 +</​code>​ 
 + 
 +===== 12. Firewalls =====
  
-In the previous chapter we referred to a firewall you may include to protect your Openvpn ​Server. ​ However this chapter refers to firewalls on the Client LAN that may block the VPN connection by blocking traffic on UDP port 1194.+In the previous chapter we referred to a firewall you may include to protect your OpenVPN ​Server. ​ However this chapter refers to firewalls on the Client LAN that may block the VPN connection by blocking traffic on UDP port 1194.
  
 In order to penetrate through the Client firewall your may want to try changing the port to 443 - normally reserved for https. Using TCP instead of UDP will also help. To make these change you will need to amend /​etc/​openvpn/​server.conf of the Server, from In order to penetrate through the Client firewall your may want to try changing the port to 443 - normally reserved for https. Using TCP instead of UDP will also help. To make these change you will need to amend /​etc/​openvpn/​server.conf of the Server, from
Line 807: Line 713:
 You also have to modify your Router'​s port forwarding to TCP port 443. You also have to modify your Router'​s port forwarding to TCP port 443.
  
-===== 12References ​=====+===== 13Sources ​=====
    
 (1) http://​en.wikipedia.org/​wiki/​OpenVPN (1) http://​en.wikipedia.org/​wiki/​OpenVPN
Line 817: Line 723:
 (4) http://​www.no-ip.com (4) http://​www.no-ip.com
  
 +(5) http://​roy.marples.name/​projects/​openresolv/​index
 +
 +  * Written for Slackware 14.2 in April 2018
   * Originally written by [[wiki:​user:​chrisabela | Chris Abela]]   * Originally written by [[wiki:​user:​chrisabela | Chris Abela]]
 <!-- Please do not modify anything below, except adding new tags.--> <!-- Please do not modify anything below, except adding new tags.-->
 {{tag>​howtos network openvpn}} {{tag>​howtos network openvpn}}
  

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