Flapping ports in my experience is normally to do with a loop or dodgy cable.
Can someone back sense of this flap and why so many ports/mac addresses?
This is from a 3750 the root switch which has a trunk to a 2960 on 2/0/11 and I see this from time:
And on the other end of the the trunk on the 2960 I see this:
Gig 0/24 is the trunk port back down to the 3750. Does it look like what ever is on Gig 0/2 is causing the issue?
If so why does the 3750 then flap on most of it's ports after?
check what is the device connected to that port by using show cdp neigh
Check the network switches for misconfigurations that might cause a data-forwarding loop.
check spanning-tree configuration.
Sh cdp and spanning tree look as they should.
could a look on a device beyond the 2960 cause this flap and if so why would ports on the 3750 flap too?
3750------->2960------->3 ports going to 3rd party LAN
Post the configuration to have a look for what is wrong in the configuration.
is this working and having issue recently or have you had any changes recently which causing the issue