'ip routing' command on a layer 2 switch

[amai_yuki]

our company is currently converting multiple branches to cisco devices. I got a little problem on one of the switch(3750), I can telnet and ping the switch from the router, but not from the management PC, when I compare the basic config handed by our ISP on two switches, I found the 'ip routing' command is configured on the switch in problem, after this command removed, everything works fine. I'm wondering if anyone could tell me how/why this command causes the above problem.

appreciate your help!

[Richard Burts]

Amai

Based on your description of the problem I am guessing that the switch was configured with ip default-gateway. This works on layer 2 devices to define the default gateway which the device will use to get to any remote destination. However if ip routing is enabled then the device is operating as a layer 3 device and will not use the default-gateway. As a layer 3 device it would need dynamic routes from a routing protocol, or static routes (including a configured default route) to get to remote destinations.

While the ip default-gateway will be retained in the configuration the only time that it will be used is when ip routing is disabled.

HTH

Rick

[ewang]

OR

1. enable ip routing

2. configure ip route 0.0.0.0 0.0.0.0 instead of ip default-gateway

basically it's a router without any ip routing protocols enabled.