I wonder if they mean that it will not respond to the ARP if the router
would then have to route the packet out the same interface that it came
in on.
(10.1.1.x/24) (10.1.2.x/24)
R1---------------R2--------R3--| H2
|
|
H1 10.1.x.x/16
1. If H1 (which is misconfigured) wants to send a packet to H2 it will
ARP; because it thinks H2 is local.
2. Both R1 and R2 could proxy-arp for H2.
3. If R1 proxy-arps it will then have to route the packet to R2.
4. R1 learned the router from R2 which is on the same broadcast domain
so R1 will allow R2 to do the proxy-arp.
5. R2 may not know if it has the "BEST ROUTE" to H2
but
6. R1 knows that it doesn't have the "best route" because it would have
to send it out the same interface.
I'm gonna test this out and I'll keep you posted.
DaveC
Scott Meyer wrote:
>
> Thanks for the response. Do you have the link for this?
>
> How does the router determine if it has the best route? Does routing
> protocol choice have anything to do with this determination? Using RIP for
> example, the router only knows how many hops away a network is. It knows
the
> best route to forward the packet, but doesn't know if there is another
> router with a better route that would have received the packet.
>
> Scott Meyer
> CCNA, CCDA, MCSE, etc
> [EMAIL PROTECTED]
>
> -----Original Message-----
> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]
> Sent: Wednesday, May 09, 2001 4:55 PM
> To: [EMAIL PROTECTED]
> Subject: Re: addressing/mask question [7:3727]
>
> Under proxy ARP, if the router receives an ARP Request for a host that is
> not on the same network as the ARP Request sender, and if the router has
the
> best route to that host, then the router sends an ARP Reply packet giving
> its own local data link address. The host that sent the ARP Request then
> sends its packets to the router, which forwards them to the intended host.
>
> Scott,
> That is quoted from the CCO help pages. Essentially, both of your
scenarios
> are true, except that the router only responds to the ARP if it has the
BEST
> path to the host or service sought.
> HTH,
> Rob H.
> CCNP, CCDP, MCSE, CCA
> FAQ, list archives, and subscription info:
http://www.groupstudy.com/list/cisco.html
> Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Message Posted at:
http://www.groupstudy.com/form/read.php?f=7&i=4194&t=3727
--------------------------------------------------
FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
