RE: Gateway of last resort [7:31997]

2002-01-15 Thread Kent Hundley

David,

If you point a routers GLR to its interface, the router will issue an arp
request for any destination that is unknown, even devices that are not on a
connected segment. (this is the same behavior that most host OSes exhibit if
you point their DG to their own IP)  For this to work, you must have another
device on that segment setup for proxy arp to answer those arp requests
issued by the router.  A Cisco router can act as a proxy arp device, so can
firewalls.

If you simply tell the router its GLR is a certain IP address, it doesn't
have to issue a lot of extraneous arp requests and will simply send all
traffic directly to the IP address you specified as its GLR.

Unless you have a specific reason for using proxy arp, its best practice to
just tell the router specifically who its GLR is. (there are certain
redundancy scenarios where the use of proxy arp might be useful)

HTH,
Kent

-Original Message-
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of
Peck, David
Sent: Tuesday, January 15, 2002 7:29 AM
To: [EMAIL PROTECTED]
Subject: Gateway of last resort [7:31997]


I was under the impressions that the gateway of last resort was a actual
interface on the router. if a router had two interfaces one 10.1.1.1/16 and
10.1.2.1/16 and 10.1.2.1 was connected to a firewall that has a address of
10.1.2.2 that the gateway of last resort would be 10.1.2.1 not 10.1.2.2 and
the static route thru 10.1.2.1 would be 0.0.0.0/0 [1/0] via 10.1.2.1 not
0.0.0.0/0 [1/0] via 10.1.2.2 or does this matter ?
Thanks




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Re: Gateway of last resort [7:31997]

2002-01-15 Thread Steven A. Ridder

I understand the gateway of last resort to be the destination of where the
traffic should be forwarded.  Hence gateway, not "local interface of last
resort"  :)

It really dosen't matter if on a point-to-point network, because you'd
forward the traffic out the interface and the other side would pick it up.
I'd imagine that on a multi-access netowrk such as ethernet where you had
three or more routers, if you just blasted the default traffic out the
interface, no one would pick it up if it wasn't destined to them.

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