User`s manual

BIPAC-74x Series Router – 741 GE, 741 GE V2.0 and 743 GE

Chapter 3: Basic Installation and Configuration

110 TCP POP3 (Post Office Protocol Version 3)

119 TCP NEWS (Network News Transfer Protocol)

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.

In addition to specifying the port number to be used, you will also need to specify the protocol

used. The protocol used is determined by the particular application. Most applications will use

TCP or UDP, however you can specify other protocols using the drop-down Protocol menu.

Setting the protocol to “all” will cause all incoming connection attempts using all protocols on all

port numbers to be forwarded to the specified IP address.

DMZ: The DMZ Host is a local computer exposed to the Internet. When setting a particular

internal IP address as the DMZ Host, all incoming packets will be checked by the Firewall and

NAT algorithms, then passed to the DMZ host when a packet received does not use a port

number used by any other Virtual Server entries.