The Port Forwarding Screen - ZyXEL Communications VMG1312-B Series User Manual

Chapter 11 Network Address Translation (NAT)
WAN side. When t he response com es back, NAT t ranslat es t he dest inat ion address ( t he inside
global address) back t o t he inside local address before forwarding it t o t he original inside host .
Port Forwarding
A port forwarding set is a list of inside ( behind NAT on t he LAN) servers, for exam ple, web or FTP ,
t hat you can m ake visible t o t he out side world even t hough NAT m akes your whole inside net work
appear as a single com put er t o t he out side world.
Finding Out More
See Sect ion 11.8 on page 196

11.2 The Port Forwarding Screen

Use t he Por t For w a r din g screen t o forward incom ing service request s t o t he server( s) on your
local net work.
You m ay ent er a single port num ber or a range of port num bers t o be forwarded, and t he local I P
address of t he desired server. The port num ber ident ifies a service; for exam ple, web service is on
port 80 and FTP on port 21. I n som e cases, such as for unknown services or where one server can
support m ore t han one service ( for exam ple bot h FTP and web service) , it m ight be bet t er t o
specify a range of port num bers. You can allocat e a server I P address t hat corresponds t o a port or
a range of port s.
The m ost oft en used port num bers and services are shown in
t o RFC 1700 for furt her inform at ion about port num bers.
Not e: Many resident ial broadband I SP account s do not allow you t o run any server
processes ( such as a Web or FTP server) from your locat ion. Your I SP m ay
periodically check for servers and m ay suspend your account if it discovers any
act ive services at your locat ion. I f you are unsure, refer t o your I SP .
Configuring Servers Behind Port Forwarding (Example)
Let 's say you want t o assign port s 21- 25 t o one FTP , Telnet and SMTP server (A in t he exam ple) ,
port 80 t o anot her ( B in t he exam ple) and assign a default server I P address of 192.168.1.35 t o a
186
for advanced t echnical inform at ion on NAT.
Appendix F on page 359. Please refer
VMG1312-B Series User's Guide