Router not Learning Mac address

[joel.moore]

Have a 7600 running Hybrid mode. when we plug a new device into the switch side we are unable to see the device untill we ping its IP from the router side. WHen you ping the device the first packet no response then the rest of them come back. Before you ping the deivce the arp table does not show it. Once you ping it the device shows up in the arp table. There is no complex routing going on on it. It is only a a vlan router. Any help would be great.

Joel Moore

Lan Anaylst

[steve.busby]

This is normal behavior. Devices won't show in the router's ARP table until they generate some type of traffic, in this case your ICMP echo back to the router.

Now if you're on the device and initiate traffic (ping, telnet, http,etc) then go to the router, does the device's MAC Address show up in your ARP table?

[joel.moore]

That is the strange part. The device is not able to ping anything untill the router has pinged it. And the mac only will show up after the router has pinged it.

[steve.busby]

Can you post the applicable interface configuration? Also the results of a "sho interface" on the applicable interface.

The "device" you're talking about is a workstation/server or another switch/router?