We have a 2950 Switch connected to a Cisco router, and a Mitel server.
The switch has VLAN 1 and 100 configured on it - all ports being in both. We have voice traffic on VLAN100.
When I try to enable VLAN100, VLAN1 shuts off.
All ports are configured as access-ports.
My goal is to have the switch forward packets to the router to a branch site, if needed, and vise versa.
Am I going to have to enable trunking and interVLAN routing on both the switch and the router?
It sounds to me like you are doing the right things. If you can not access the Mitel, then I suspect that it is some issue on the Mitel. If they are going to check the Mitel server I believe the obvious things to check include that its configured IP address and netmask are as you expect them to be and that they match what you configured on the router subinterface. Also check to verify that the default gateway configured is the address configured on the router subinterface.
I also wonder if it could be an issue with ping. Some servers are configured in a "hardened" mode and may not respond to ping as a policy. While tracert from a Windows PC uses ping (and is not useful for the immediate purpose) traceroute from the Cisco router uses UDP packets. So it might be useful to traceroute from the router to the Mitel and see if there is any response. Or have the folks at the site see if they can access anything from the Mitel.
Thanks for the response. Yes you have it right: you do not need interface vlan 100 on the switch and attempting to no shut it will result in interface vlan 1 going into shutdown.
Whether interface vlan 100 exists or not (is up or down) does not really have anything to do with the switch forwarding frames at layer 2. What what you have posted it looks like VLAN 100 is active at layer 2 and the switch should be forwarding frames in VLAN 100 just fine. Assuming that the trunking is configured correctly and the subinterfaces on the router are right, then the router should be able to access the server in VLAN 100.