I have a client with servers connecting to my Cisco Nexus switches on trunked interfaces. The switch ports are configured with a native VLAN, being the server's primary VLAN for PXE boot, and a second VLAN for VM clients. The client would like to be able to identify the VLANs allowed on the trunk from the server-end, so he can verify the configuration when troubleshooting PXE boot or VM connectivity issues.
Is there a protocol that is transmitted, or can be transmitted, in broadcast that should allow a packet capture to reveal all VLANs permitted on a trunk? I know we can learn the native VLAN, but I'm looking for a way for the server to "hear" the whole VLAN range.
everyone's help is greatly appreciated.
Dan