How to set up VPN server in linux

I will show you how to configure a VPN server with pptpd. It can also be installed with L2TP or OpenVPN. I have not tried the later.


1) Install ppp in the server
2) Download pptpd-1.3.4-2.rhel5.x86_64.rpm in the server
3) Install the downloaded pptpd rpm package in the server
4) Edit IP setting in the pptpd.conf (/etc/pptpd.conf) you will have to specify the server
   address and the network range (localip,remoteip)
5) Add user accounts in /etc/ppp/chap-secrets (assign username and password)
   in the specified format.
   ---------------------------------------------------------
   # client    server    secret            IP addresses
     rasimvs pptpd password *
   ---------------------------------------------------------
6) You can also do the optional settings of DNS resolver
   /etc/ppp/options.pptpd

    ms-dns 8.8.8.8
    ms-dns 4.4.4.4
7) Enable Network forwarding in /etc/sysctl.conf
     net.ipv4.ip_forward = 1
     sysctl -p
8) Configure firewall rules using the following commands

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iptables -A INPUT -i eth0 -p tcp --dport 1723 -j ACCEPT
iptables -A INPUT -i eth0 -p gre -j ACCEPT
iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE
iptables -A FORWARD -i ppp+ -o eth0 -j ACCEPT
iptables -A FORWARD -i eth0 -o ppp+ -j ACCEPT
service iptables save
service iptables restart
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9) Add pptp to check config so that it is started on restarts 
    chkconfig pptpd on

10) restart the pptpd service or may be restart theserver.


Command summary on this regard.

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yum install ppp
cd /usr/local/src/ 
wget http://lnmpp.googlecode.com/files/pptpd-1.3.4-2.el6.x86_64.rpm 
rpm -Uvh pptpd-1.3.4-2.el6.x86_64.rpm
vi /etc/pptpd.conf 
vi /etc/ppp/chap-secrets 
vi /etc/ppp/options.pptpd 
vi /etc/sysctl.conf 
sysctl -p
iptables -A INPUT -i eth0 -p tcp --dport 1723 -j ACCEPT
iptables -A INPUT -i eth0 -p gre -j ACCEPT
iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE
iptables -A FORWARD -i ppp+ -o eth0 -j ACCEPT
iptables -A FORWARD -i eth0 -o ppp+ -j ACCEPT
service iptables save
service iptables restart
chkconfig pptpd on
getenforce  
vi /etc/selinux/config 
init 6
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