My employer is expanding we are installing some new servers and a new 2960G 48 port switch. After spending countless hours of trying to figure out why 2 of the 3 servers were not talking correctly, I started looking more at the switch. Seems there are four ports that are not working correctly. Ports 9, 10, 11 and 12. The equipment plugged in there can get a DHCP lease, but anything as far as file transfer etc (in Windows Server 2003) fails.

I've switched cables, and NICS, no luck. Moving the gear to ports other than 9-12 and everything works fine.

Plugged a laptop in to port 9 and started pinging a server. Small packet sizes are no trouble. But larger packets seems to drop at about 35%.

using win XP, i ping a file server with a 3 byte packet for a couple hours with 100% success.

300 byte packet gets 35% drop rate.

Has anyone ever seen something like this before?

How could I troubleshoot the issue? Nothing is being logged on the switch. The POST process has no errors (laptop plugged into the console port to see messages) I wiped out the config and started over with the nearly blank cisco defaults, same thing.

It's a new switch, so the vendor is gonna swap it. But I'd like to know what I could have done to save myself all the hours I've been messing with this. I barely know my way around the CLI, is there some kind of test I can trigger that would find an issue like this?