Configure Linux VPN Server

Configure Linux VPN Server
Install poptop

sudo apt-get update
sudo apt-get install pptpd

Type ifconfig and inspect the "eth0" section to find out the IP address of your server [inet addr]
edit pptpd.conf
I use nano at the terminal, you may use any text editor

sudo nano /etc/pptpd.conf

change lines
localip 10.5.1.3 (this address should be the IP address of your server [inet addr] when you type ifconfig,
see above )
remoteip 10.5.1.241-246

Above allocation assigns 6 IP addresses for 6 roaming users/telecommuters to VPN into your corporate network
simultaneously.

sudo nano /etc/ppp/options

find the line that says ms-dns, modify the IP addresses to suit your local environment.
These two IP addresses should be the IP addresses of the DNS servers provided to you by your ISP/cable/ADSL company.
Don't use other DNS servers as they may block queries that come from outside their network environment.
ms-dns 216.21.128.22
ms-dns 216.21.129.22

sudo nano /etc/ppp/chap-secrets
e.g.
alice pptpd a-strong-password *
bob pptpd another-strong-password *

The trailing * means these users are allowed to come in from any IP address, if the telecommuter or branch office has a static or fixed IP address and never roams, then you can replace the * with his/her fixed IP address (or IP address block) for increased security.

One more tweak is to instruct the Linux kernel to "forward" VPN packets

I tried with no results to change
sudo nano /etc/sysctrl.conf
find the line that says:
#net.ipv4.conf.default.forwarding=1
delete the #
save the file.
reboot
This was from the web address i gave earlier.

What worked for me was.

I made a shell file named "ipforward"
#!/bin/sh
sysctl -w net.ipv4.ip_forward=1

Than made it executable
sudo chmod +x /etc/init.d/ipforward

Than updated rc.d

sudo update-rc.d FOO defaults