RealVNC connections over the internet through a router

[jcm]

I need some help with RealVNC connections over the internet through a 
router.


INSTALLATIONS:

Here is a summary of the RealVNC installations...

   ISP: Comcast, Ewing, NJ

   Router: Netgear WGR614v6, no firmware upgrades

   Computers: Several Dells and a Compaq DeskPro, 200MHz to 863MHz

   OS's: Windows XP Pro SP2 and SP3, Win98, Redhat Linux v6.2

   RealVNC Versions: v4.0 and v4.1.3, Free Personal


All of the computers that were tested are hooked-up via wire.  There are 
no wireless complications.


SETUP:

I used the router's "LAN IP Setup" option to permanently assign a unique 
internal IP for each computer's unique MAC address (e.g. MAC address 
03:02:E3:22:53:D4 will always have an IP address of 192.168.1.2).

I used the router's "Port Forwarding" option to direct traffic to the 
correct internal IP address for each computer (e.g. Port 5902 goes to 
internal IP address 192.168.1.2).


SYPTOMS:

The following is true (and the same) for most combinations of the 
Computers, OS's, and RealVNC Versions mentioned above.  For the purpose 
of testing, I've disabled all firewall activity (i.e. Windows Firewall 
and ZoneAlarm)...

1. I can use RealVNC Viewer successfully when specifying internal LAN 
addresses such as: 192.168.1.2:5902 and 192.168.1.7:5907.  Additionally, 
"wireless" RealVNC Viewer connections also work when using internal LAN 
addresses.

2. RealVNC Viewer fails to connect when I try to use my Comcast internet 
address (e.g. 76.99.228.120 or 76.99.228.120:2 or 76.99.228.120:5902 or 
76.99.228.120:7 or 76.99.228.120:5907).  The reported RealVNC Viewer 
error is: "unable to connect to host: Connection timed out (10060)".

3. There may be a router or ISP issue because everything used to work 
fine (a year and/or two ago), but I swapped-out the router from an old 
LinkSys router to the newer Netgear router.  In the past, I used to be 
able to use the RealVNC Viewer with Comcast internet addresses, with no 
problem, using IP addresses such as: 76.99.228.120:2 and 
76.99.228.120:7.  I don't have the time-resolution to determine if the 
problem lies with the router-swap or with Comcast changing some 
protocol.  I've tested the system using several of my friend's computers 
in other towns.  And again, using other systems, it used to work before, 
but it doesn't work now.


Does anyone have any ideas?


Thanks,

jcm