Strange GET request

IE6 on Windows XP

[bobriggs]

UA: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1)

I think that's how XP id's itself (NT 5.1)?

I'm seeing this in my logs:
2 404's were generated while a page loads along with the regular graphics and external CSS page, all in the same second (i.e., user didn't type them in). The requests were for these pages:

GET /_vti_bin/owssvr.dll?UL=1&ACT=4&BUILD=2614&STRMVER=4&CAPREQ=0 HTTP/1.1
and
/MSOffice/cltreq.asp?UL=1&ACT=4&BUILD=2614&STRMVER=4&CAPREQ=0 HTTP/1.1

So if they're browser generated, what is it for? Is this an XP thing?

[Key_Master]

I could be wrong but I believe NT 5.1 is Windows2000. I don't know what XP is yet.

<added>Checked my log files. I can confirm "Windows XP" in the User Agent string. There are probably more.

[evinrude]

Similar question was asked on one of SecurityFocus' email lists. The question can be found Here [lists.jammed.com].

To quote a portion of the answer they received:

IE will query the server to see if it supports web
discussions. This query will only happen if the user has the discussion
bar turned on.

[ralnikov]

Key_Master: win2k is winnt 5.0 and winxp is nt 5.1