VirtualBox: Slow network, bad checksums and retransmissions

less than 1 minute read

OK, I’ve to admit that I still use Windows for some tasks, even worse it’s Windows Vista. The good point is that I use a virtualised version running on VirtualBox.

Unfortunately I faced some trouble with my network connection being quite slow while accessing network drives and internal server while the internet seemed to work very fine. I got so annoyed meanwhile that I started an investigation with <a href=”http://www.wireshark.org>Wireshark</a> and figured out that I have lot’s of error messages.

Most of them are incorrect TCP checksums, but quite a lot of retransmissions as well (besides all the broadcasts that you see in a Windows network which one could consider as errors as well ;-) ). Searching the net revealed that TCP checksum offloading could be the root of all evil which I found at Winfuture forum.

Especially the post about registry entries solved the problem for me eventually.

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters
"DisableTaskOffload"=1