Nailed-Up Connection (Ppp); Nat; Metric; Traffic Redirect - ZyXEL Communications P-793H v3 User Manual

6.5.5 Nailed-Up Connection (PPP)

A nailed-up connection is a dial-up line where the connection is always up regardless of traffic
demand. The P-79X does two things when you specify a nailed-up connection. The first is that idle
timeout is disabled. The second is that the P-79X will try to bring up the connection when turned on
and whenever the connection is down. A nailed-up connection can be very expensive for obvious
reasons.
Do not specify a nailed-up connection unless your telephone company offers flat-rate service or you
need a constant connection and the cost is of no concern.

6.5.6 NAT

NAT (Network Address Translation - NAT, RFC 1631) is the translation of the IP address of a host in
a packet, for example, the source address of an outgoing packet, used within one network to a
different IP address known within another network.

6.6 Metric

The metric represents the "cost of transmission". A router determines the best route for
transmission by choosing a path with the lowest "cost". RIP routing uses hop count as the
measurement of cost, with a minimum of "1" for directly connected networks. The number must be
between "1" and "15"; a number greater than "15" means the link is down. The smaller the
number, the lower the "cost".
The metric sets the priority for the P-79X's routes to the Internet. If any two of the default routes
have the same metric, the P-79X uses the following pre-defined priorities:
• Normal route: designated by the ISP (see
• Traffic-redirect route (see
For example, if the normal route has a of "1" and the traffic-redirect route has a metric of "2", then
the normal route acts as the primary default route. If the normal route fails to connect to the
Internet, the P-79X tries the traffic-redirect route next.
If you want the traffic-redirect route route to take priority over the normal route, all you need to do
is set the traffic-redirect route's metric to "1" and the normal route to "2".
IP Policy Routing overrides the default routing behavior and takes priority over all of the routes
mentioned above.

6.7 Traffic Redirect

Traffic redirect forwards traffic to a backup gateway when the P-79X cannot connect to the Internet.
An example is shown in the figure below.
Chapter 6 WAN Setup
Section 6.2 on page
Section 6.7 on page 61)
P-79X Series User's Guide
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46)