A general firewall question

Using a WinXP sp3 stand-alone machine connected directly to a broadband ISP.


In order to participate in the Code Project Tech Summit on Visual Studio
2010, I went to a website for a compatability check, to verify the required
software was installed on my machine.

In addition, it checked that the Firewall and Proxy servers were open, which
they were. I thought "Open? What's open?"

I went into my Firewall settings, which were on, with no exceptions. The
only services that internet users could access was the VAIO Media SSDP
Multicast for my LOcal Area Connection.

Is that Multicast the only thing that the Tech Summit needed access to? Is
that what they meant by "Firewall and Proxy Servers open"?

Are there other settings that do not show up in the Windows Firewall dialog
box that Microsoft (and possibly others) are accessing without our knowing
it?

Are there other places in the WinXP environment where Firewall settings are
controlled?