5 technical reference – ZyXEL Communications Prestige P-870HW-51a v2 User Manual

Page 112

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Chapter 8 Network Address Translation (NAT)

P-870HW-51a v2 User’s Guide

112

The following table describes the fields in this screen.

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.

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

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.

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

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