Chapter 8 Network Address Translation (NAT)

The following table describes the fields in this screen.

Table 30 NAT - DMZ Host

LABEL

DESCRIPTION

Default Server

Enter the IP address of the default server which receives packets from

 

ports that are not specified in the NAT Port Forwarding screen.

 

Note: If you do not assign a Default Server, the ZyXEL Device

 

discards all packets received for ports that are not specified

 

in the NAT Port Forwarding screen.

 

 

Save

Click Save to save your changes back to the ZyXEL Device.

 

 

8.5 Technical Reference

The following section contains additional technical information about the ZyXEL Device features described in this chapter.

Port Forwarding: Services and Port Numbers

The most often used port numbers are shown in the following table. Please refer to RFC 1700 for further information about port numbers. Please also refer to the Supporting CD for more examples and details on port forwarding and NAT.

Table 31 Services and Port Numbers

SERVICES

PORT NUMBER

ECHO

7

 

 

FTP (File Transfer Protocol)

21

 

 

SMTP (Simple Mail Transfer Protocol)

25

 

 

DNS (Domain Name System)

53

 

 

Finger

79

 

 

HTTP (Hyper Text Transfer protocol or WWW, Web)

80

 

 

POP3 (Post Office Protocol)

110

 

 

NNTP (Network News Transport Protocol)

119

 

 

SNMP (Simple Network Management Protocol)

161

 

 

SNMP trap

162

 

 

PPTP (Point-to-Point Tunneling Protocol)

1723

 

 

Port Forwarding Example

Let's say you want to assign ports 21-25 to one FTP, Telnet and SMTP server (A in the example), port 80 to another (B in the example) and assign a default server IP address of 192.168.1.35 to a third (C in the example). You assign the LAN IP

112

 

P-870HW-51a v2 User’s Guide