Hi, I have to submit an assignment for my university in which I have to make a FTP server and allow my professor to access through Internet I am using Dlink DSL-2750B and tries to open FTP port 21 through port forwarding in Dlink router but received an error ""Since port 21 is used as FTP remote access port, external port range [21-21] is invalid" and does not add the FTP port so please help me in this regard
Thanks & regard,
Osama Faheem