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VLAN traffic leak?

chrpalmer
Level 1
Level 1

While capturing packets on our Cat 4006 (Sup III/IOS) switch, I noticed that I am receiving frames for other unicast hosts that belong to my VLAN.

The destination MAC addresses are known by the switch, and are mostly out it's int port-channel1 (connected to another Cat 4006 SupII/CatOS).

No SPAN or port monitoring is enabled.

CAM aging time is default (5 min).

The ports/interfaces in question are configured as switchport access (no trunking, etc).

I have rebooted both switches: no change.

The problem seems to be occurring for other hosts on the same VLAN. I configured a port for a different VLAN and picked up traffic for hosts on that different VLAN.

Any help is appreciated...thanks, Christopher

1 Accepted Solution

Accepted Solutions

There are a few different reasons for this. One of the more common occurs when using HSRP and having asymetrical routing going on. Check out Cisco's doc on unicast flooding.

http://cisco.com/en/US/products/hw/switches/ps700/products_tech_note09186a00801d0808.shtml

View solution in original post

1 Reply 1

There are a few different reasons for this. One of the more common occurs when using HSRP and having asymetrical routing going on. Check out Cisco's doc on unicast flooding.

http://cisco.com/en/US/products/hw/switches/ps700/products_tech_note09186a00801d0808.shtml

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