The Windows 7 machines in my office have been losing connectivity with the server for the last few days. In an effort to resolve the issue, I ran an ARP flush on all Windows 7 clients and the server. Initially, all seemed well. MAC addresses were correct, and all Windows 7 machines could ping the server (and vice-versa). Ten minutes ago, I tried to ping the server again from one of the Windows 7 machines and it failed. Sure enough, a bad MAC address had snuck back into the laptop's ARP cache.
Something evil out there in the network is causing this ARP cache corruption. What are my prime suspects?