Vista - Windows 2008 NAT corrupts downloads

Downloads behind Routing and Remote access are getting corrupted.

1. If I set up routing on the server beside it, and change my gateway everything works so I know it's not the hardware or the ISP.

2. If I download a file to the problem server, and then move it via windows networking, the file is fine and works, so it's not even the hardware in the server itself.

3. I've tried turning off and on .. QOS, IPV6.

4. I've removed and re-installed the Routing and Remote access.

5. I've thrown a hissy fit and swore diligently at the machine using all known expletives.

Any suggestsions

Interesting. The same NAT driver is used by ISA servers, and probably many other "firewall" solutions, so I doubt it's the NAT itself.

Does the file type make a difference?

Have you tried multiple sources?

Are the resultant files truncated or corrupted despite showing up as being the correct size?

Does the same issue occur if you boot the server to [safe mode + net]?

What anti-virus solution is installed on the Win2k8 server? Can you test what happens if you remove it temporarily?

File type makes no difference, althought the error is different. Zip files report CRC errors, Executables report several different errors depending on OS, but mainly the file is not readable.

I have tried a dozen sources at least.

The files are the right size, and have the same byte count as the good downloads I can do if I use the other server as a gateway instead.

There is currently no antivirus software running. (I'm going to load McAfee and do a scan, but I control the UAC and never let anything install via web etc so I doubt that is it)

I haven't tried the safe mode option. I'll have to come in late night to do that, but thanks for that idea.

Does anyone know if 127.0.0.1 should ping on Win 2008? Localhost pings to ::1 which seems normal with vista so I suspect normal here, but 127.0.0.1 doesn't ping at all.

A weird and complex problem indeed. However, since there doesn't seem to be a general outcry that IPNAT.SYS in win2k8 chews data, the most likely explanation is some as-yet-unknown environmental factor - a driver which is interfering, most likely.

I'd suggest testing what happens in [safe mode + net]. Afterwards, try disabling "chimney" (TCP offload), RSS, and NetDMA.

If all that still produces consistently wonky results, I'd beg/borrow/steal a different NIC as a test. While I realise that the results of your previous testing do not suggest any obvious hardware involvement, the interaction between all these kernel-mode components is very complex.