Inside my LAN at home I can connect to any machine without any problems. When I upgraded the vnc server on the XP box at my fathers home I used to be able to connect to it from my house before from my W2k machine at home and now when I try and connect to it I get a blank screen and it ask me for the password it accepts it and then I cannot get past that point, the screen just sits there and then it times out(my father uses a dial up connection and I have high speed). Also I have never been able to connect to his machine from my home through linux. This is the command that
I have used:

vncviewer -LowColourLevel -Preferredencoding raw XXX.XXX.XXX.XXX

I do not get any prompt for a password from linux.

What is going on?

Try to put xxx.xxx.xxx.xxx:5800 or xxx.xxx.xxx.xxx:5600 in the VNC program.

It can also be a firewall or tunnelling problem. Also, try to set up a DNS server in the host, and desactivate QoS (quality of service), firewall settings - or let it accept 5800 and 5900 manually) and any procolol like ´NetBIOS´ and ´Ipx´. Let only TCP active.

See if VNC for linux is in the beta version. IF so, try to get a lower stable version (not so ancient). Do the same with Windows VNC. Good luck

VNC only works if both computers are connected somehow. So, if your father's machine uses a dial-up connection and isn't connected to the internet, then you can't reach it via the internet.

Can you do a telnet to port 5900 (or 5800) on your father's machine?
If that doesn't work:
-either the connection is down
-or there's an intervening firewall/security measure.

Did your father recently upgrade to XP SP2?

Let me explain a little better. I used to be able to connect before. This is how:

My fathers give me his client IP on his network. XXX.XXX.XXX.XXX
On his firewall I have opened up port 5900 and enable java connection and port 5800 and have it listening for a call under the admin properties in UltraVNC.On my w2k machine I just put in XXX.XXX.XXX.XXX(the default port is 5900 in UltraVNC). I log in and the screen goes black. If I try to connect using java through my web browser XXX.XXX.XXX.XXX:5800, I log in and it just sits there. If I use Vnc through linux by type vncviewer XXX.XXX.XXX.XXX, it just sits there. I used to be able to before. I ran some MS updates on his XP box and thats when it started. I am so sick of windows.

Yes, but did that include the installation of Service Pack 2 (SP2)?
If it did, you may need to go to the Win XP control panel, click on firewall config and configure XP's firewall to allow access to the VNC port(s).

I've read somewhere that Windows may have an option to allow/disallow VNC ("remote assistance").
You may need to enable that as well.

Perhaps you can also take a look at:
http://jsifaq.com
http://support.microsoft.com

He does have XP service pack 2 and I have opened up those ports on his firewall under windows firewall section,then exceptions and then add ports, 5800 tcp,5900 tcp. Those freaking security patches that i ran must have screwed something up.

Maybe you can also look at
http://www.microsoft.com/technet/security/default.mspx

Rolling back patches is possible, but not advisable in view of the many security holes in Windows.