On Tue, Apr 21, 2009 at 11:44:47AM -0500, Sean Carolan wrote:
How can I find out which port on the switch a particular server is connected to? I was hoping that this is somehow possible using the mac address and the data gathered from snmpwalk/snmpget requests but I'm not having much luck. How would you tackle this problem?
My notes: http://wiki.xdroop.com/space/snmp/Switching+Tables
Basically there are at least two places in snmp where this might be stored. The most obvious is the classic MIB-II Bridge. The wrinkle with this MIB is that some switches maintain separate tables for each VLAN, which means in order to query the switch properly, you have to query the MIB for each VLAN.
Newer switches populate the Q-Bridge-MIB instead of or as well as the MIB-II Bridge. This table contains the VLAN that the target MAC is reachable through, which is useful since you don't have to know it ahead of time.
We have a six- or seven- year old cisco 3750 which is running an IOS which doesn't have the newer MIB; for this switch, we must explicitly query the MIB-II Bridge for each VLAN. I would hope that newer relesaes of IOS wouldn't have this limitation.