For a management application I need to retrieve the mac-address that a switch uses when tagging the remote-id field of dhcp requests when dhcp snooping is enabled. Specifically, when dhcp nooping is enabled, the remote-id field in a dhcp packet contains a mac-address of the switch on which the dhcp'ing client is attached.
I would like to know what the mac-address is that will be specified and if that is available in a MIB. On our C4500 it will be the first mac-address specified by doing:
sh module 1
but that is not availabe on our C3500 switches.
I can get the mac-address+1 by looking at the BIA of the first available interface:
sh int gi1/1
This is great by I need to find a MIB that makes this available.
On our C300 switches the mac-address can be determined by looking at ENTITY-MIB::entLogicalContextEngineID
but that doesn't give anything meaningful on the C4500.
What about ifPhysAddress for the first interface in each switch? That is, get the ifIndex for the first interface (i.e. Gi1/1 on the 350 and the interface which matches pattern '.*Ethernet1/[0-9]+' on the 4500), then do an SNMP Get on ifPhysAddress.INDEX.