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--- playground:openvpn_-_how_to_set_up_a_slackware_server_and_a_slackware_client [2013/12/27 19:19 (UTC)] – chrisabela
+++ playground:openvpn_-_how_to_set_up_a_slackware_server_and_a_slackware_client [2018/03/02 00:05 (UTC)] – old revision restored (2014/10/12 20:01 (UTC)) bifferos
@@ Line 138: / Line 138: @@
 </code>
-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: cleint1), but you may choose any name.
+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.
 Copy pki/reqs/client1.req back to the Server.
@@ Line 183: / Line 183: @@
 <code>
-# cp openvpn-2.3.2/sample/sample-config-files/server.conf \
+# cp openvpn-*/sample/sample-config-files/server.conf \
 > /etc/openvpn/
 </code>
@@ Line 538: / Line 538: @@
 daemon
 </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.
+Copy the rc.openvpn listed hereunder and place under /etc/rc.d/</note>
+<code>
+#!/bin/sh
+#
+# /etc/rc.d/rc.openvpn
+#
+# Start/stop/restart the openvpn server.
+#
+ovpn_start() {
+  if [ -x /usr/sbin/openvpn -a -r /etc/openvpn/server.conf ]; then
+    echo "Starting OpenVPN:  /usr/sbin/openvpn server.conf"
+    /usr/sbin/openvpn /etc/openvpn/server.conf
+  fi
+}
+ovpn_stop() {
+  killall openvpn
+}
+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>
+Then give it executable permissions:
+<code>
+# chmod 755 /etc/rc.d/rc.openvpn
+</code>
+Eventually when you start openvpn on the server, you may read /var/log/openvpn.log to verify that your work has been successful:
+<code>
+# cat /var/log/openvpn.log
+</code>
 ===== 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.
-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 =====
-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>
-# cp /usr/doc/openvpn-2.2.2/sample-config-files/client.conf \
+# cp /usr/src/openvpn-*/sample/sample-config-files/client.conf \
 > /etc/openvpn/
 </code>
@@ Line 583: / Line 641: @@
 </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.
+<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 lines. This should help you a lot in the configuration process.</note>
-You will need the following files that were generated by the easy-rsa scripts:
+You will need the this files that were generated by the Client's easy-rsa scripts:
+<code>
+/root/easy-rsa/easyrsa3/pki/private/client1.key
+</code>
+and the following from the Server's easy-rsa scripts:
 <code>
 ca.crt
-client1.crt
-client1.key
 ta.key
 </code>
+You will also need client1.crt generated by the Server as explained above in Chapter 5.2.1.
 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/
-Copy the following rc.openvpn-client listed hereunder and place under /etc/rc.d/
+Also in client.conf, comment out the line:
 <code>
-#!/bin/sh
+ns-cert-type server
-#
+</code>
-# /etc/rc.d/rc.openvpn-client
-#
-# Start/stop/restart the openvpn client.
-#
-ovpn_start() {
+and insert the line:
-  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
+remote-cert-tls server
-}
-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>
-Then give it executable permissions:
+My full client.conf is the following:
 <code>
-# chmod +x /etc/rc.d/rc.openvpn-client
+##############################################
-</code>
+# Sample client-side OpenVPN 2.0 config file #
+# for connecting to multi-client server.     #
+#                                            #
+# This configuration can be used by multiple #
+# clients, however each client should have   #
+# its own cert and key files.                #
+#                                            #
+# On Windows, you might want to rename this  #
+# file so it has a .ovpn extension           #
+##############################################
+# Specify that we are a client and that we
+# will be pulling certain config file directives
+# from the server.
+client
+# Use the same setting as you are using on
+# the server.
+# On most systems, the VPN will not function
+# unless you partially or fully disable
+# the firewall for the TUN/TAP interface.
+;dev tap
+dev tun
+# Windows needs the TAP-Win32 adapter name
+# from the Network Connections panel
+# if you have more than one.  On XP SP2,
+# you may need to disable the firewall
+# for the TAP adapter.
+;dev-node MyTap
+# Are we connecting to a TCP or
+# UDP server?  Use the same setting as
+# on the server.
+;proto tcp
+proto udp
+# The hostname/IP and port of the server.
+# You can have multiple remote entries
+# to load balance between the servers.
+remote servervpn.no-ip.org 1194
+;remote my-server-2 1194
+# Choose a random host from the remote
+# list for load-balancing.  Otherwise
+# try hosts in the order specified.
+;remote-random
+# Keep trying indefinitely to resolve the
+# host name of the OpenVPN server.  Very useful
+# on machines which are not permanently connected
+# to the internet such as laptops.
+resolv-retry infinite
+# Most clients don't need to bind to
+# a specific local port number.
+nobind
+# Downgrade privileges after initialization (non-Windows only)
+user nobody
+group nobody
+# Try to preserve some state across restarts.
+persist-key
+persist-tun
+# If you are connecting through an
+# HTTP proxy to reach the actual OpenVPN
+# server, put the proxy server/IP and
+# port number here.  See the man page
+# if your proxy server requires
+# authentication.
+;http-proxy-retry # retry on connection failures
+;http-proxy [proxy server] [proxy port #]
+# Wireless networks often produce a lot
+# of duplicate packets.  Set this flag
+# to silence duplicate packet warnings.
+;mute-replay-warnings
+# SSL/TLS parms.
+# See the server config file for more
+# description.  It's best to use
+# a separate .crt/.key file pair
+# for each client.  A single ca
+# file can be used for all clients.
+ca /etc/openvpn/certs/ca.crt
+cert /etc/openvpn/certs/client1.crt
+key /etc/openvpn/keys/client1.key
+# Verify server certificate by checking
+# that the certicate has the nsCertType
+# field set to "server".  This is an
+# important precaution to protect against
+# a potential attack discussed here:
+#  http://openvpn.net/howto.html#mitm
+#
+# To use this feature, you will need to generate
+# your server certificates with the nsCertType
+# field set to "server".  The build-key-server
+# script in the easy-rsa folder will do this.
+;ns-cert-type server
+remote-cert-tls server
+# If a tls-auth key is used on the server
+# then every client must also have the key.
+tls-auth /etc/openvpn/keys/ta.key 1
+# Select a cryptographic cipher.
+# If the cipher option is used on the server
+# then you must also specify it here.
+;cipher x
+# Enable compression on the VPN link.
+# Don't enable this unless it is also
+# enabled in the server config file.
+comp-lzo
+# Set log file verbosity.
+verb 3
+# Silence repeating messages
+;mute 20
+#</code>
 ===== 9. Testing the VPN =====
@@ Line 649: / Line 806: @@
 <code>
-# /etc/rc.d/rc.openvpn-server start
+# /etc/rc.d/rc.openvpn start
 </code>
+Enter the Server PEM pass phrase when prompted.
 On the Client:
 <code>
-# /etc/rc.d/rc.openvpn-client start
+# /usr/sbin/openvpn /etc/openvpn/client.conf
 </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:
 <code>
-# ifconfig tun0
+# /sbin/ifconfig tun0
 tun0: flags=4305<UP,POINTOPOINT,RUNNING,NOARP,MULTICAST>  mtu 1500
         inet 10.8.0.1  netmask 255.255.255.255  destination 10.8.0.2
@@ Line 674: / Line 835: @@
 <code>
-# ifconfig tun0
+# /sbin/ifconfig tun0
 tun0: flags=4305<UP,POINTOPOINT,RUNNING,NOARP,MULTICAST>  mtu 1500
         inet 10.8.0.6  netmask 255.255.255.255  destination 10.8.0.5
@@ Line 782: / Line 943: @@
 <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 -A OUTPUT -o eth0 -j ACCEPT
-  # Policies
+  $IPT -A OUTPUT -o tun0 -j ACCEPT
-  $IPT -P 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 -m conntrack --ctstate ESTABLISHED,RELATED -j ACCEPT # Allow responses
+  $IPT -A INPUT -m conntrack --ctstate ESTABLISHED,RELATED -j ACCEPT # allow responses
-  $IPT -A INPUT -j SERVICES # Append the services chain to the input
+  $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 -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
+  $IPT -t nat -A POSTROUTING -s 10.8.0.0/24 -o eth0 -j MASQUERADE
-  # Allow services
+  # allow sshd on the default tcp port 22
-  # Allow vpn on the default udp port 1194
+  #$IPT -A SERVICES -p tcp --dport 22 -j ACCEPT # Uncomment to allow sshd
-  $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 non-default tcp port 443
+  $IPT -A SERVICES -p tcp --dport 443 -j ACCEPT
+  echo "done."
 }
 firewall_stop() {
+  echo -e "Stopping the firewall ....\c"
-  # Polcies (permissive)
+  # polcies (permissive)
+  $IPT -P OUTPUT ACCEPT
   $IPT -P INPUT ACCEPT
+  $IPT -P FORWARD ACCEPT
-  # Flush the iptables
+  # flush the iptables
   $IPT -F
-  # Delete the services custom chain
+  # delete the services custom chain
   $IPT -X SERVICES
-}
+  echo "done."
+}
+firewall_status() {
+  $IPT -vL
+}
 case "$1" in
@@ Line 842: / Line 1018: @@
   firewall_start
   ;;
+'status')
+  firewall_status
+  ;;
 *)
-  echo "Usage $0 start|stop|restart"
+  echo "Usage $0 start|stop|restart|status"
 esac
 </code>
@@ Line 859: / Line 1038: @@
 </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:
+<code>
+# /etc/rc.d/rc.openvpn restart
+</code>
+and reconnect from the Client:
+<code>
+# /usr/sbin/openvpn /etc/openvpn/client.conf
+</code>
 ===== 11. Firewalls =====
@@ Line 911: / Line 1100: @@
 You also have to modify your Router's port forwarding to TCP port 443.
-===== 12. References =====
+===== 12. Sources =====
 (1) http://en.wikipedia.org/wiki/OpenVPN

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