3 machine running VNC behind NAT router?

[Michael Lande]

I'll admit it. I'm a newbie. How do pick which machine to login to?

A friend help me get started with VNC on WinXP so I could provide  
remote support for a client of mine. I wanted to be able to login to  
the PC which is behind a cable modem and a DHCP router. All is well  
on the first PC. My friend had me open up ports 5850 - 5950 on the  
firewall which is a DLink router. We also found the current IP  
address for the WinXP PC which I obtained from whatismyip.com. It is  
a dynamic ip address from the cable company and it hasn't change yet  
(6 weeks, same ip).

 From my office I am able to login to the WinXP PC across the internet.

Now I installed RealVNC on 2 more WinXP boxes at my clients location.  
When I went to whatismyip.com to see the ip address of these 2 new PC/ 
VNC servers they report the same ip address that I use to login to  
the first PC.

I'm using Chicken of the VNC. For the machine I have been  
successfully logging into I use Host = 24.15.XX.XXX Display = 0  
Password = XXXXX. I thought I read somewhere that for the second PC/ 
VNC server I use Display = 1, third PC - Display = 2.

I am not able to login to the 2 new PC's that I installed RealVNC on  
today. How do I login to PC#2 and PC#3? The password is the same on  
all 3 VNC setups.

Any help would be greatly appreciated.
Thanks.
Mike