Server A and Server B both are connected with Switch1. Both the servers are running with 100 Mbps Full Duplex and both the switch ports are configured with Auto. But the server A connected port showin as 100 MB Half Duplex. Because of this I am getting slow connectivity and the interface Output error also increasing gradually.
This server was working fine before. Suddnely its speed was down and when I checked the switch found the switch port is operating on a-Half 7 a-100. How it will happen automatically. Which one is faulty Server's NIC or Switch port.
Have you applied any service packs/patches/updates or updated any software recently? Something must have changed - but in a way that's academic. The main point, as d_jabsd rightly says, is that you either need to have auto at both ends of the link or have both ends fixed at the same speed/mode
I have seen this happen with old NIC drivers. I would hard code the server and the switch ports to 100 Full and see if that works. If not try to use a new network cable and if that fails upgrade the NIC drivers.