How does Auto-Update detect it has an Internet connection

The Automatic Update feature of XP (set to
automatically download & install critical updates) has
recently started to fail on all our PCs that are within
our company's internal network. The internal network has
connectivity to the internet via a proxy. The web based
windows update software works fine. My assumption is
that the Automatic Update software no longer detects that
it has an internet connection, probably because the
target URL (or whatever it uses) is being blocked by our
firewalls. If I knew what the Automatic Update software
used to determine if it had an internet connection, then
I could investigate if the firewall was indeed blocking
access. Thanks
- steve

does your proxy route ICMP packets? (that is, can you ping
windowsupdate.microsoft.com from a proxy'd machine?) that would be my first
guess.

"Steve Krapes" <s-k-r-a-p-e-s@att.com> wrote in message
news:033401c36825$c6039cb0$a501280a@phx.gbl...

> The Automatic Update feature of XP (set to
> automatically download & install critical updates) has
> recently started to fail on all our PCs that are within
> our company's internal network. The internal network has
> connectivity to the internet via a proxy. The web based
> windows update software works fine. My assumption is
> that the Automatic Update software no longer detects that
> it has an internet connection, probably because the
> target URL (or whatever it uses) is being blocked by our
> firewalls. If I knew what the Automatic Update software
> used to determine if it had an internet connection, then
> I could investigate if the firewall was indeed blocking
> access. Thanks
> - steve