How to Enable GRE Protocol 47 on a Linksys WRT54g Wireless Router

by Jonah Quant

In computer networking, a virtual private network is a set of encrypted connections set over public networks, so that remote hosts can communicate securely by using the same applications they would use if they were physically co-located. The Generic Route Encapsulation Protocol 47 is a mechanism on top of which networks implement VPNs. Like every VPN solution, GRE 47 depends on all routers and switches traversed by the connection to not block the network messages the protocol needs to function. In particular, you can configure a Linksys WRT54G wireless router to allow GRE 47 connections.

Connect a computer to any of the ports labeled "1" through "4" on the WRT54G.

Log in to the computer.

Launch a Web browser on the computer and point it to address "" The configuration utility for the WRT54G will come up within the Web browser.

Enter the administrator password for the router, then press "Enter" to log in.

Click on "Applications & Gaming," then on "Port Range Forward." Choose any unused line in the table titled "Port Range." Type "GRE 47" under the "Application" column and "1723" under both the "Start" and "End" columns. Select "TCP" under the "Protocol" column, then enter the Internet Protocol address of the computer that will need to use GRE 47 in your local network. Click "Save Settings." At that point, the WRT54G will be configured to allow the selected computer(s) to communicate with the outside world over a VPN based on GRE 47.

Items you will need

About the Author

Jonah Quant has been writing about computer science since 1990. He has contributed to international conferences and journals such as those of the Institute of Electrical and Electronics Engineers and the Association for Computing Machinery. Quant has a Ph.D. in computer science from the University of California.

Photo Credits

  • photo_camera Thomas Northcut/Photodisc/Getty Images