[83668] in North American Network Operators' Group
RE: Rip again!
daemon@ATHENA.MIT.EDU (Chris Ranch)
Sun Aug 21 14:19:09 2005
Date: Sun, 21 Aug 2005 14:15:40 -0400
From: "Chris Ranch" <CRanch@Affinity.com>
To: <swm@emanon.com>, "Tom Sanders" <toms.sanders@gmail.com>,
<nanog@nanog.org>
Errors-To: owner-nanog@merit.edu
In case no one else has suggested it: the source MAC address will
identify the source.
Chris=20
> -----Original Message-----
> From: owner-nanog@merit.edu [mailto:owner-nanog@merit.edu] On=20
> Behalf Of Scott Morris
> Sent: Sunday, August 21, 2005 9:21 AM
> To: 'Tom Sanders'; nanog@nanog.org
> Subject: RE: Rip again!
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> How about the source IP?
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> RIP v1 is sent to 255.255.255.255 broadcast. RIPv2 is sent=20
> to 224.0.0.9 multicast. Both are local-link only, so won't=20
> go THROUGH a router. The sending source IP will tell you=20
> where they came from.
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> If you're using VLANs (trunks), there won't be any issues. =20
> If you're using
> secondary addresses, this will depend on whose devices you=20
> use. In the
> Cisco world, packets will always be sourced from the primary=20
> IP address on an interface. And if the receiving router=20
> doesn't have a subnet matching the sender, packets/updates=20
> are ignored. (Again, Cisco world you can use "no=20
> validate-update-source" to override this check)
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> But that gives you a tracking method on packets. =20
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> Scott=20
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> -----Original Message-----
> From: owner-nanog@merit.edu [mailto:owner-nanog@merit.edu] On=20
> Behalf Of Tom Sanders
> Sent: Sunday, August 21, 2005 12:13 PM
> To: nanog@nanog.org
> Subject: Rip again!
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> Hi,
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> There isnt IMO a way in RIP to identify the source of the RIP=20
> packet (the way we have Router ID in OSPF, system ID in ISIS, etc.)
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> Now assume we have 2 vlans defined on an ethernet. Thus we=20
> would have two IP interfaces, 1.1.1.1/24 and 2.2.2.2/24 and=20
> both using the same physical interface. RIP is running on=20
> both these interfaces.
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> My doubt is that how will another router, which is configured=20
> in the same way (2 vlans) be able to differentiate between=20
> the RIP responses originated by 1.1.1.1 and 2.2.2.2?
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> Thanks,
> Toms
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