ZyXEL Communications ZyXEL ZyWALL USG-1000, User Manual

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Chapter 12 Policy and Static Routes
ZyWALL USG 2000 User’s Guide
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12.4 Policy Routing Technical Reference
Here is more detailed information about some of the features you can configure in
policy routing.
NAT and SNAT
NAT (Network Address Translation - NAT, RFC 1631) is the translation of the IP
address in a packet in one network to a different IP address in another network.
Use SNAT (Source NAT) to change the source IP address in one network to a
different IP address in another network.
Port Triggering
Some services use a dedicated range of ports on the client side and a dedicated
range of ports on the server side. With regular port forwarding, you set the port(s)
and IP address to forward a service (coming in from the remote server) to a client
computer. The problem is that port forwarding only forwards a service to a single
IP address. In order to use the same service on a different computer, you have to
manually replace the client computer's IP address with another client computer's
IP address.
Port triggering allows the client computer to take turns using a service
dynamically. Whenever a client computer’s packets match the routing policy, it
can use the pre-defined port triggering setting to connect to the remote server
without manually configuring a port forwarding rule for each client computer.
Gateway IP Select the radio button and enter the IP address of the next-hop
gateway. The gateway is a router or switch on the same segment as your
ZyWALL's interface(s). The gateway helps forward packets to their
destinations.
Interface Select the radio button and a predefined interface through which the
traffic is sent.
Metric Metric represents the “cost” of transmission for routing purposes. IP
routing uses hop count as the measurement of cost, with a minimum of 1
for directly connected networks. Enter a number that approximates the
cost for this link. The number need not be precise, but it must be 0~127.
In practice, 2 or 3 is usually a good number.
OK Click OK to save your changes back to the ZyWALL.
Cancel Click Cancel to exit this screen without saving.
Table 74 Network > Routing > Static Route > Add (continued)
LABEL DESCRIPTION