I'm having big troubles when adding this Dell switch to my network.
Here we use several VLANs to segment traffic. All switches (3com and DLink mostly) have configured the same VLANs, most ports are 'untagged' and belong to a single VLAN, except for the ports used to join together the switches (in a star topology), these ports belong to all VLANs and use 802.1Q tags. So far, it works really well.
But on this new switch (a Dell PowerConnect 5448), the settings are very different (and confusing). I have configured the same VLANs, an the uplink ports are set in 'general' mode (supposed to be fully 802.1Q compliant), I can set the VLAN membership as 'T' on these ports for all VLANs except VLAN 1. It always stay as 'U' on VLAN 1.