I am testing pushvnc which I believe is a variant on realvnc. On the little domain I have set up here at home, at the win2003 server, logged in as admin, I can connect to a winxp notebook on the domain as long as it's firewall is turned off. However if I turn on the firewall, even with both 5900 and 5800 are open (tcp), the connection times out with error 10060. I don't get it...what else can I do?
Assuming this fails after you've also tried enabling 5800 and 5900 UDP, you should next define the names of the executables as part of the target XP's firewall profile.
If that still fails, you need to ensure Memory Exeuction Prevenetion is also disabled in the target XP's box.
Also enable FWQ logging at the target XP system to capture successfula nd failed connection attempts the PUSH VNC client is attempting.
iF THAT still fails, then push the VNC paCkage to an XP FW disabled target and use an IP <==> exe utility to model what is happening such as TCPview.exe (go look it up) to model which ports are being used.
Then, create your exemption rule from a the observed ports and used exe's and use that data to create your XP FW exemption ruleset and push it using any method from a regedit or a TELNET session.
XP Firewall is fairly unreliable bugger and it's rule / exemption set should still be considered BETA. Combiend with the fact you're using officially unsupported and freely available VNC for remote access is enough ingredients for a heaping bowl of frustration soup.