Before going on to tell how to get DD-WRT secured with VPN, it is important to determine whether your router is compatible with DD-WRT or not.
Most commonly used wireless routers including Linksys, Cisco, D-Link, Verizon, Sitecom and TP-Link are DD-WRT compatible.
Check out whether your router’s name appears in this compatibility list for DD-WRT. http://www.dd-wrt.com/wiki/index.php/Supported_Devices

The following are the easy set up instructions for configuring a VPN on your DDWRT router. I have made used PPTP router settings to install VPN, mainly because PPTP is the easiest and most preferred protocol for DDWRT routers. You can also install DDWRT router VPN on other encryption protocols like OpenVPN.

  1. First, make sure that your router is flashed from your vendor’s website. You may get it flashed from DD-WRT Website using v24sp2 or higher version.
  2. Next, go to the control panel of your DDWRT account, click the VPN tab under ‘Services’ and hit ‘Enable’ on the option for radio button. This will turn on the support for PPTP VPN server.
  3. Now, you will find various options for PPTP VPN server configurations which you need to fill up in the manner below.
  4. Server IP: Enter IP address of your router.
  5. Client IP: Enter the Local IP addresses of the client computers or devices connected through the VPN.
  6. CHAP-Secrets: Fill in the Username and password to authenticate the VPN connection in the format, (user[space]*[space]password[space]). Each line should contain the entry of only one user.
  7. Once these entries are done, press the “Apply Settings” button to save the configuration on your DD-WRT router.
  8. Now connect all client computers and devices to your VPN. The process for Windows is given here.
  9. Go to control panel and navigate Network and Sharing Centre. Click the option “set up a new set up a new network connection or network”.
  10. In the window that opens, click on Connect to a Workplace and then choose Create a New Connection from the next screen.
  11. Next, hit “Use my internet connection” to choose the mode for your VPN. A screen will appear with the following fields: IP address/ domain name and connection name. Fill your IP address for DD-WRT router you configured just now and name the connection as per your choice.
  12. Write the username and password with which you originally configured your DDWRT router and hit ‘Connect’.
  13. Check the status of your VPN and internet connection by running the ‘ipconfig’ on your computer. If it shows your provider name along with DDWRT router information, you have successfully established PPTP VPN on your router.