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New Member

I want to know the practical use of 0.0.0.0 IP

Pls forward how to use this IP in practical application.

3 REPLIES
Cisco Employee

Re: I want to know the practical use of 0.0.0.0 IP

0.0.0.0 is a reserved IP address that is used to designate the default route.

From a host standpoint it typically refers to a lack of an IP address.

HTH

New Member

Re: I want to know the practical use of 0.0.0.0 IP

Hi All,

0.0.0.0, to my understanding, is used often, in static routes, to set a route path. For example, "route outside 0.0.0.0 0.0.0.0 192.168.1.1 1" on a PIX would direct all packets out the outside interface to 192.168.1.1 which is 1 hop away, as shown by the last 1 in the entry. Correct me if I'm wrong, somebody. Cheers.

coolboarderguy...

Green

Re: I want to know the practical use of 0.0.0.0 IP

Address 0.0.0.0 with a mask of 0.0.0.0 is the Default Route (aka :"Gateway of Last Resort")

It's a fairly popular convention in that Microsoft uses it, *nix uses it, Cisco uses it, and pretty much every other piece of networking equipment in recent history uses it.

The Default Route can be entered as a static route (ip route 0.0.0.0 0.0.0.0 {next hop address or interface ID} {Optional (but rarely used for Default route) Metric}. The Default can also be learned through a routing protocol or DHCP assignment.

FWIW

Scott

This has the ring of "a homework question" ...

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