Hi Cisco Support Community.
I posted earlier about this but have not found resolution. However, I have learned some more about the problem.
Here is a portion of the network.
On switch gc2960, we want to have clients on vlan 29 and vlan 27. We are connected over trunk port between switch gc2960 and the stack ch3750.
We used to have it connected to the switch ch3550 but it exhibited the same issue... I plan to retire the 3550 switch so that's why we're on the 3750 now.
The connection is on a fractional T1, split out by Adtran 850 units at either end. Both devices are connected to the ethernet interfaces of their Adtran 850's. I don't know if this makes a difference, but the other units are connected via other means and work as expected.
When native vlan 29 is NOT set, we can ping, telnet, resolve dns, etc. but we simply cannot use any web browser (firefox or ie both). It times out when browsing to anything. I use netstat -a on the client pc and I see the outbound connections on port 80. I know that data is coming back to at least the unit ch3750. This is both to targets on the internet, as well as for things on other parts of our organization's network such as a print server web management interface.
When native vlan 29 is set at both ends of the trunk, we can browse the web using firefox, ie, etc as expected from client pc's on vlan 29 on the gc2960 switch. But vlan 27 clients get the issue where they cannot browse, but can ping, do dns, telnet, etc.
What I am thinking is: for some reason, the "high ports" are not getting back to the clients on vlan 29 or vlan 27 unless we set the native vlan.
Why on earth would this be the case? I am stymied by this. Thanks for your comments.
