Poor network response and intermittent TCP resets, generally noticed through SSH clients like putty, can be painful.
If you suspect a duplicate IP address could be the issue, then the following tool can be used to check:
arping -c2 -w3 -D -I eth? <IP address>
This will check for duplicates on the eth? net of the IP passed.
-D engages duplicate checking,
-c 2 sends 2 requests,
-w 3 waits for 3 secs per request.
If there is a duplicate this command will identify it.