Keith, since you are running an FTP server, you need to tell your router to send all FTP requests to your computer. (Insteaf of other computers on your router's network)
Find the ip address for your computer. (use the command IPconfig in a DOS window)
In your router's settings there will be something called Port Firewarding or Virtual Servers, etc.
Usally it looks like this:
PORT RANGE IP ADDRESS PORT RANGE
Fill in the information. It will probably look something like this:
20-21 192.168.2.11 20-21
The first Port Range is the ports your local machine is using.
Ip address is your ip address for your local computer.
The second port range is the port range that the internet will be sending their information on.
Think of it like this: INTERNET TRAFFIC is sent on port 21 to the router's IP address: 67.23.15.20 --> YOUR ROUTER ----> The router directs the specific FTP traffic to Port 21 of your computer. Make sense?
Hope that helped. If not, read your router's manual about how to foreward traffic. It is a lot easier- for you and us.
Enjoy!
Note: Some ISPs block traffic on certain ports- 21 is the standard FTP port. If you are sure you configured it right, go into Serv-U's settings and change the ftp server's Port to something like 2121 or 9999, then change the router's Port forewarding settings to foreward those ports also.
if you still have trouble, msg me on aim: ohnonotmoreteeth I can help only for a little bit- any more help and I'd ask for something in return. :]
Hope it works!
Last note: Whenever, wherever you ask a question, it is best to give ALL the information you can. I'm glad you mentioned Serv-U FTP. but it would have helped if you had mentioned your Router's model ## as well. A well-detailed question gets an detailed answer. Otherwise, we are shooting in the dark. And no one likes to be shot, right?