I want to share Filemaker Pro 7.0 with associates via the internet.  I
have obtained an account with ip2go to solve the problem of changing
IP address by ISP, but don't know how to configure by router's
filewall... Motorola WR850G.  The port being used by Filemaker is 591.
 IP2GO has given me the following additional information: "Having a
name like foxencreekstudios.ip2go.us is exactly one of the things you
need.  I just ran an nMap scan from the "internet" (actually from
ippages.com) against that name of yours, and it found the IP address
as 24.185.233.252 and no "open" ports, but all ports are "filtered",
which I believe indicates your firewall is controlling all access to
this computer."

Ok, first you need to open that port via the router. First open up a
web browser, and use your router address (commonly http://192.168.2.1/
or http://192.168.2.100/). Then search through the settings for a
firewall or NAT/Virtual Server setting. You'll want to open up port
591, as specified. However, you'll need to figure out whether it's TCP
or UDP, as the firewall on your router, and the software firewall (if
you're using one) will probably ask for that as well. Also, if you
haven't set a password on your wireless router, now would be a good
time to do so!

Next, you'll need to open the port on your software firewall on your computer. 

For the windows firewall, you can find instructions here:
http://support.microsoft.com/default.aspx?scid=kb;en-us;308127

These instructions should be relatively similar to any other firewall
out there. Just look for an "exceptions" setting, and input the port
number and type to open it.

Good luck!