I am seeing a strange traffic pattern when sniffing a segment of my network.
To explain, at the network core is a 4500 Cat switch with a number of vlans, the vlan in question is configured as follows
description **First Floor**
ip address 10.3.6.2 255.255.254.0 secondary
ip address 10.3.2.2 255.255.255.0 secondary
ip address 10.3.3.2 255.255.255.0 secondary
ip address 10.101.254.252 255.255.0.0
Connected to the 4500 is a Cat2960, which is connected via a dot1q trunk. All VLAN's on the 4500 are trunked to this switch.
All ports on this switch are access ports in vlan 102.
I connect my laptop to one of the switch ports on the 2960, my laptops IP address is 10.101.10.125.
When running Ethereal and capturing packets, I can see a stream of traffic from a host with IP address of 10.102.15.34 (this subnet lies in another building connected via a WAN link) to a host with address of 10.3.3.12. The stream is a unicast UDP stream to port 8080.
I can't understand why I should see this from my host, there is also no port mirroring configured.
I've connected to other ports on this switch and other switches with ports in the same VLAN with the same result.
Any ideas ?