If the port on the switch is not up to par, sometimes that is just a physical issue. Normally the contacts are just bent wire that is more or less spring loaded to make contact when the patch cable is pushed into the port. In that case, sometimes a wire will get a little out of tollerance for some connectors. When that happens, you can pull the wire up a little and see if that fixes it. I have fixed a few switches and NICs in this manner only one of them ever had a problem again (it was a poorly constructed switch anyway).
If it is a smaller, less expensive switch, I would just replace it and cut your losses in labor. If it is more expensive, you may consider putting some electricians tape accross the port so it can't be mistakenly used again. In a pinch I have seen this "repair" work for a couple switches that otherwise performed perfectly for a couple years.
- Tom
