Changing the DNS query timeout in Windows XP

I've been having some networking trouble lately. When my PC laptop is busy downloading a file, Windows XP starts failing to resolve DNS queries. So even simple lookups that I know must be cached at multiple levels, like www.google.com, start failing to resolve. Windows just times out after fifteen seconds and gives up.

Needless to say, this makes web browsing while downloading a file insanely frustrating.

My Mac laptops don't seem to have the same problem. I have no idea whether this is a problem with my ISP, my wireless router, Windows itself, or some combination of the three. And frankly, as an end user I don't care and shouldn't have to care. I just want it to stop sucking.

I set out to see if I could increase the client-side DNS timeout so that Windows would be a little more forgiving about slow DNS responses. It turns out there is a way to do that, though it's nearly impossible to find via a web search. (Even Windows experts, which I make no claim to be, seem to have trouble with this one because it's so obscure.)

Here's the registry setting to increase the DNS client-side timeout in Windows 2000 and XP:

HKEY_LOCAL_MACHINE \ SYSTEM \ CurrentControlSet \ Services \ Tcpip \ Parameters \ DNSQueryTimeouts

[Update Nov 3, 2006: Fixed the above link. It used to point here, but that link now redirects you to the main page for the Windows 2000 resource kit. Remember, kids, cool URLs don't change.]

Read the above link for details. The registry entry does not exist by default; you have to create it. I don't suggest you do this lightly unless you're familiar with using regedit to tweak parameters.

The default value when the property isn't present is documented to be "1 2 2 4 8 0", which appears to represent that 15-second total timeout. (15 = 1 + 2 + 4 + 8. It's not clear to me exactly what the other 2 is for; it may be redundant.)

I wanted something a little longer, so I quadrupled all the numbers to "4 8 8 16 32 0".

Now I have a 60-second total timeout, with the final query given 32 seconds to get through. In practice this has proven to be a long enough timeout that Windows can continue to resolve DNS names even when my network connection is busy.

And that's good news. I'm much happier again, and I can continue to use my PC laptop without wanting to chuck it out the window every time I download a file.