From: ALL From_NJ (all.from.nj@gmail.com)
Date: Tue Feb 03 2009 - 16:51:26 ARST
Well ... the cool thing is that the default behavior is for the check to be
on. I never saw the split horizon comment until I looked this up, so as I
understand it, with or without split horizon, this check will happen. Did
you find different?
I forgot all the 'rules and caveats' with this ... but having secondary
addressing on a peer neighbor can cause some problems.
If updates are sourced from the secondary address, and this secondary
address is from another network than the peering router, then you would need
to use the 'no' keyword in order for rip to accept the updates.
On Tue, Feb 3, 2009 at 12:17 PM, Rsharma <cciers09@gmail.com> wrote:
> Hi ,
>
> Just want to knw the reason behind it that Disabling split horizon on the
> incoming interface cause the system to perform this validation check .
>
> I tried this with Dynamip lab and its correct but i wasnt able to co-relate
> Split Horizon with Validate check .
>
> Thanks!!!!!!
> Rsharma :-)
>
> ALL From_NJ wrote:
>
>> I am learning to search the docs ... I have a feeling I will need them!!!
>> ;-)
>>
>> Here is a link to this command (watch the ugly word wrap):
>>
>> http://www.cisco.com/en/US/docs/ios/iproute/command/reference/irp_rip.html#wp1012874
>>
>> Copied and pasted from the link:
>>
>> To have the Cisco IOS software validate the source IP address of incoming
>> routing updates for Routing Information Protocol (RIP) and Interior Gateway
>> Routing Protocol (IGRP) routing protocols, use the validate-update-source
>> command in router configuration mode. To disable this function, use the no
>> form of this command.
>>
>> validate-update-source
>> no validate-update-source
>>
>> ---->>>> Usage Guidelines
>>
>> This command is applicable only to RIP and IGRP. The software ensures that
>> the source IP address of incoming routing updates is on the same IP network
>> as one of the addresses defined for the receiving interface.
>>
>> Disabling split horizon on the incoming interface will also cause the
>> system to perform this validation check.
>>
>> For unnumbered IP interfaces (interfaces configured as IP unnumbered), no
>> checking is performed.
>> Examples
>>
>> The following example configures a router not to perform validation checks
>> on the source IP address of incoming RIP updates:
>>
>> router rip
>> network 10.105.0.0
>> no validate-update-source
>>
>> HTH,
>>
>>
>>
>>
>> On Mon, Feb 2, 2009 at 1:43 PM, Rsharma <cciers09@gmail.com <mailto:
>> cciers09@gmail.com>> wrote:
>>
>> Hi,
>>
>> Validate Update source command in RIPv2 n IGRP .
>> What exactly is being scanned by protocol to validate ....????
>>
>> can anyone zoom on Validate action ??
>>
>> Thanks
>> Rsharma
>>
>>
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>>
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>>
>>
>> --
>> Andrew Lee Lissitz
>> all.from.nj@gmail.com <mailto:all.from.nj@gmail.com>
>>
>
>
-- Andrew Lee Lissitz all.from.nj@gmail.comBlogs and organic groups at http://www.ccie.net
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