It turns out that hardware can fail in weird ways. Its not common, but it appears that it is not uncommon that the memory in a network device can go bad. When this happens, lots of packets are corrupted. I have a description of how I think this happens: <a href="http:&#x2F;&#x2F;www.evanjones.ca&#x2F;tcp-and-ethernet-checksums-fail.html" rel="nofollow">http:&#x2F;&#x2F;www.evanjones.ca&#x2F;tcp-and-ethernet-checksums-fail.html</a>