ZyXEL Communications MAX208M2W SERIES, User Manual

Page: 91 / 200

Chapter 7 Network Setting
MAX208M2W Series User ’ s Guide
91
The Version field controls the format and the broadcasting method of the RIP
packets that the MAX208M2W Series sends (it recognizes both formats when
receiving).
RIP-1
is universally supported; but RIP-2 carries more information.
RIP-1 is probably adequate for most networks, unless you have an unusual
network topology.
Both
RIP-2B
and
RIP-2M
sends the routing data in RIP-2 format; the difference
being that RIP-2B uses subnet broadcasting while RIP-2M uses multicasting.
Port Forwarding
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.
With port forwarding, you can 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.
For 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 33
Multiple Servers Behind NAT Example