I have a Windows 2003 SBS at home and because Windows doesn’t support VLANs natively, I use Vmware to run a virtual opensuse router. This works perfectly fine for all systems except for the host OS itself. On my host OS, my download speed was around 3.5 MB/s, which is just fine, but the upload was only around 20 kB/s, which is less than 1/50 of what should be possible. After 2 nights of searching, I finally found the culprit. I used Bridged networking for the connection between Host, Guest and all other PCs in the network, but Vmware seems to have a problem with this setting. Switching to host-only networking solved the problem for the host, but disabled the guest talking with other PCs. So I added a new virtual network adapter in Vmware, making one host-only and the other bridged. After removing the old gateway and setting the Hosts Gateway to the host-only IP of the guest, everything is now lightning fast.