Billion Electric Company 7560G - Manual (Page 117)

Billion BIPAC-7560/7560G Powerline(802.11g) ADSL VPN Firewall Router
Chapter 4: Configuration
123 UDP NTP (Network Time Protocol)
161 TCP SNMP
443 TCP & UDP HTTPS
1503 TCP T.120
1720 TCP H.323
4000 TCP ICQ
7070 UDP RealAudio
Because NAT can act as a “natural” Internet firewall, your router protects your network from
being accessed by outside users when using NAT, as all incoming connection attempts will
point to your router unless you specifically create Virtual Server entries to forward those ports to
a PC on your network. When your router needs to allow outside users to access internal servers,
e.g. a web server, FTP server, Email server or game server, the router can act as a “virtual
server”. You can set up a local server with a specific port number for the service to use, e.g.
web/HTTP (port 80), FTP (port 21), Telnet (port 23), SMTP (port 25), or POP3 (port 110), When
an incoming access request to the router for a specified port is received, it will be forwarded to
the corresponding internal server.
For example, if you set the port number 80 (Web/HTTP) to be mapped to the IP Address
192.168.1.2, then all incoming HTTP requests from outside users will be forwarded to the local
server (PC) with the IP address of 192.168.1.2. If the port is not listed as a predefined
application, you need to add it manually.
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