I am adding an SG300 to replace an aging 2950x and am having an issue getting tagged VLAN traffic to pass from the SG300(1) to the secondary SG300(2). I have configured port ge51 on both SG300s in trunk mode and allow tag multiple vlans. I also have configured port ge52 on the SG300(1), and port fe2/0/6 on the 2950 in the same way. SG300(1) and the 2950 have been happily passing traffic for months. However, even after a factory reset and reconfig on SG300(2) the only passed traffic is the default vlan. The SG300(2) is new and running firmware 126.96.36.199. This should be simple stuff, but I am at a loss.
try and configure the trunk ports as 'General':
VLAN Management > Interface Settings > Interface VLAN Mode > General
and/or explicitly specify the native VLAN:
switchport trunk native vlan 1
stupid question maybe, but do the VLANs you are trying to trunk actually exist on both SG300 switches ?
just another thought: can you check if you have VTP enabled on the 2950 and the other SG300 by any chance ?
I can't check the 2950 without going on-site. I will check and get back to you. Thanks for the continued help.