Just by looking at what you said it is working correctly , you have a duplex mismatch just by whbat you said . You said you set the switch to auto and the nic is hard at 100/full , this is a mismatch , can't do this . If you have the switch as auto then the server nic must be set as auto or you must hardcode the nic at 100/full and the switch as 100/full. When you set the port as auto if the server is set as 100/full then the switch can always sense the speed but it cannot sense duplex unless the server nic is set to auto , then the switch defaults to 100/half by design so that is what youi are seeing .
Cat 6506 with a 48-port user card (WS-X6248-RJ-45). When we plug a server into one of it's port (ie. 2/10) it shows up as 100/Half after setting the port to auto. We have verified that the NIC is running at 100/Full, but the switch shows it as running 100/Half. I've tested the board to make sure that there's no hardware issue and everything comes out clean. When I statically configure 2/10 for 100/Half it comes back with a duplex-mismatch (bc the NIC is really 100/Full). Any ideas why this is happening?