Technical Reference; Figure 56 Multiple Servers Behind Nat Example; Table 31 Services And Port Numbers - ZyXEL Communications P-870HW-51a v2 User Manual

8.4 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
ECHO
FTP (File Transfer Protocol)
SMTP (Simple Mail Transfer Protocol)
DNS (Domain Name System)
Finger
HTTP (Hyper Text Transfer protocol or WWW, Web)
POP3 (Post Office Protocol)
NNTP (Network News Transport Protocol)
SNMP (Simple Network Management Protocol)
SNMP trap
PPTP (Point-to-Point Tunneling Protocol)
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 addresses and the ISP
assigns the WAN IP address. The NAT network appears as a single host on the Internet.

Figure 56 Multiple Servers Behind NAT Example

P-870HW-51a v2 User's Guide
Chapter 8 Network Address Translation (NAT)
PORT NUMBER
7
21
25
53
79
80
110
119
161
162
1723
103