We had two switches, 4104g and 4108g, uplinked togather on 1Gbps ports and these ports are tagged for one of the VLANs. Here is the issue, I pulled the Gig module, where most of the servers were plugged in, from the 4108 switch and swapped it with one 10/100Mbps module from the 4104 switch. So, now we have all desktops plugged into the 4108 switch and all the switches plugged into the 4104 switch. The switches were uplinked with a 100Mbps ports, and the tagging was done as follows: Default_VLAN= NO, Desktop_VLAN= Untagged, so we started having issues. Servers weren't talkint to remote servers and part of the network lost connectivity to the switch. When I moved all the servers to the 4108 switch, connectivity to remote servers got reestablished. Can someone explain to me what mistakes were made here to cause this mishap?