User's Manual Part 20

Common application port values:
Application
Port values Type
FTP 21 TCP
Web Server 80 TCP
Telnet 23 TCP
While all the ports of the PC in the DMZ are exposed to the Internet, Port
Forwarding only allows the ports that you specified to be opened up. DMZ can
be understood as a form of Port Forwarding where ALL the ports are forwarded.
DMZ is usually easier to set up, but Port Forwarding is more secure. For the
user accessing from the Internet, DMZ and Port Forwarding are basically similar
in function.
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