i'm behind linksys router, and i had problems with one app not connecting to internet because of built in firewall. i used port forwarding and it worked. then i learned DMZ feature, when i did that i didnt need any kind of forwarding. now the question is, why is that no enough for serv-u ftp server to work fine? users could connect to server but not download something. then after screwing around with it i found out that if i use "allow passive mode data transfers, use ip :xxx.xxx.xxx.xxx" and if i put my isp assigned ip it works. even though i have dsl my ip is dynamic and changes. do i just have to update my ip in that setting box everytime i want ftp to work? or is there another way?