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DHCP - ARP Issue on 6509's

pbunchuk
Level 1
Level 1

I have a problem that has recently started. When a host renews a DHCP lease or releases and renews and IP address the host can ping other vlans and the Inet gateway but cannot get out to the internet or access resources on a diffternet vlan.

When the arp cache is cleared on the core switch with the issue is resolved. The hosts are on two 6509's with CatOS 5.5.1. The core is a 6509 with Sup2-2GE & MSFC2, CatOS 6.1.2, Msfc2 12.1(3a)E4.

3 Replies 3

bwhitaker
Level 1
Level 1

Question....When you say you are clearing the arp cache on the core switch. Can you give me a little more detail about what you are actually doing?

When a host on the access switches (6509's) renews and address and receives one from DHCP he cannot access the network beyond his on Vlan.

If he is given a static IP the problem is resolved, or if the DHCP IP is kept and the arp cache on the core/distribution swicth (6509 w/msfc2) is cleared (on the msfc) the issue is resolved.

Did you receive a resolution on this issue? I have a similar situation where DHCP clients can ping any default gateway address on the 6509 but cannot ping hosts on other vlans. After waiting several minutes, then they are able to access the entire network.