VNC works over local network, not internet

[Nick]

I have 2 XP pcs connected by a netgear wireless
router. CompA is configured w. VNC at the default
Display Number. CompB is at Display Number 1. My
router is configured to pass 5900 to CompA, and
5901 to CompB.

I can use VNCViewer to connect to CompA by
entering mydomain.dyndns.org (details withheld),
but entering mydomain.dyndns.org:1 does not
connect to CompB. Error msg is 'Failed to connect
to server'.

However, I can run VNCViewer on CompA and
successfully connect to CompB:1, so I know that
VNC is working on CompB.

Neither computers have ICF enabled.

Any suggestions would be appreciated.

 

[Bill Sanderson]

Try mydomain.dyndns.org:5901

 

[Nick]

Thanks for that suggestion, but it doesn't work
(mydomain.dyndns.org:5900 does work, though).

CompB is a newer computer than CompA. Did MS
change XP in any way? I wonder. It seems like
CompB is blocking remote access, but Internet
Connection Firewall is not enabled on it (I must
have check 5 times).


"Bill Sanderson"
message

 

[Bill Sanderson]

XP hasn't changed, except as happens with patch or SP application. I don't
know of anything that would block port 5901 except a firewall.

Is there any third-party software running on B that might include firewall
functionality?

Have you double-checked that the forwarding address on the router is still
correct?

 

[Jeffrey Randow (MVP)]

Perhaps ISP blocking of VNC now? (not that I am surprised)

 

[Bill Sanderson]

I've not worked with VNC with alternate ports before, so I don't know what
to look for. Here's a possible alternative to try.

If your router supports changing the port as it forwards inbound--many do
this, especially those supporting UPnP forwarding:

1) change the port for PC B back to the standard 5900

2) set the router to forward inbound packets on port 5901 to PC-b on port
5900.

Try connecting to the public IP of the router (from outside the router!) on
port 5901 and see what happens.

Refresh my memory about why you are doing uencrypted communication here?
This isn't safe--a VPN connection or using UltraVNC with an encryption
plugin would be better.