IP Routing

Some operating systems offer the ability to act as a router and forward IP packets from one network interface to another based on its internal routing tables. No machines on campus should have a need to do this. Because of this, IP Routing is banned.

If a machine is configured to route IP packets from one interface to another and both are on the same physical network, the packets will appear on the wire twice. As a result, ARP caches may become corrupt because two possible interfaces have received packets for one host.

When hosts are incorrectly configured as routers, information is disseminated incorrectly. In order to advertise which networks are available on other interfaces, the host must send route advertisements in one format or another. These advertisements may impair the real routers from receiving information or may cause them to advertise the incorrect routes. To be sure that you do NOT configure your operating system for IP routing:

Windows XP: Do NOT enable Internet Connection Sharing (Network Bridging).

Mac OS X: Do NOT enable Internet Connection Sharing while connected to the campus network.

Last Updated: 2/14/08