WebShare 144WN

7.3.1 Port Forwarding: Services and Port Numbers

A NAT server set is a list of inside (behind NAT on the LAN) servers, for example, web or FTP, that you can make accessible to the outside world even though NAT makes your whole inside network appear as a single machine to the outside world.

Use the SUA Server page to forward incoming service requests to the server(s) on your local network. You may enter a single port number or a range of port numbers to be forwarded, and the local IP address of the desired server. The port number identifies a service; for example, web service is on port 80 and FTP on port 21. In some cases, such as for unknown services or where one server can support more than one service (for example both FTP and web service), it might be better to specify a range of port numbers.

In addition to the servers for specified services, NAT supports a default server. A service request that does not have a server explicitly designated for it is forwarded to the default server. If the default is not defined, the service request is simply discarded.

The most often used port numbers are shown in the following table. Please refer to RFC 1700 for further information about port numbers.

ServicesPort Number/Protocol

 

File Transfer Protocol (FTP) Data

20/tcp

 

FTP Commands

21/tcp

 

Telnet

23/tcp

 

Simple Mail Transfer Protocol (SMTP)

25/tcp

 

Email

 

 

Domain Name Server (DNS)

53/tcp and 53/udp

 

Trivial File Transfer Protocol (TFTP)

69/udp

 

finger

79/tcp

 

World Wide Web (HTTP)

80/tcp

 

POP3 Email

110/tcp

 

SUN Remote Procedure Call (RPC)

111/udp

 

Network News Transfer Protocol

119/tcp

 

(NNTP)

 

 

Network Time Protocol (NTP)

123/tcp and 123/udp

 

News

144/tcp

 

Simple Management Network Protocol

161/udp

 

(SNMP)

 

 

SNMP (traps)

162/udp

 

Border Gateway Protocol (BGP)

179/tcp

 

Secure HTTP (HTTPS)

443/tcp

 

rlogin

513/tcp

 

rexec

514/tcp

 

talk

517/tcp and 517/udp

 

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