No mac address on switchport

[ppellettiere]

I have a 2851 router attached to 3750 on a l3 interconnect.

The switch sees the router with a "sh cdp neighbor" but

when you can not see the MAC address on the port the router is connected to.

Not sure why?

[cadet alain]

Hi,

if the router hasn't sent any frames then its mac address can't be in the CAM table as the dynamic entries are learnt via source address and have a timout of 5 mins by default.

Regards.

Alain.

[ameya_oke]

HI ppellettiere,

Please post response of below set of commands.

1) ping

2) sh ip arp

3) sh mac address-table interface

Ameya