icmp netowrk redirect rfc 1812

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Sep 30th, 2008
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hi,


acording to rfc 1812, router MUST NOT send network icmp redirect. But I have 4500 switch doing axactly this. So my question is if anybody else has issues with network icmp redirects.


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Richard Burts Mon, 10/06/2008 - 08:23
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Dragan


It would help if you would identify the section of RFC 1812 to which you refer, since there are MANY references in RFC 1812 about routers and redirects. Most of the references in RFC 1812 describe how a router would send redirects.


I find one reference and I wonder if it is what you were looking at. In section 5.3.12.1 When a Router Ceases Forwarding there is a statement that a router must not send redirect. But this section is talking specifically about a situation where the router has stopped forwarding (this would be the case if you configure no ip routing). But that is certainly not the situation with your equipment.


For the most part the RFC emphasizes that routers DO send redirects.


HTH


Rick


Richard Burts Mon, 10/06/2008 - 09:58
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Dragan


Thanks for the reference. It does help to clarify what you are asking about. Are you saying that your switch is sending network redirects (ICMP type 5 code 0 messages)? How are you seeing this traffic (is it in debug output, in log messages, in a packet capture)?


HTH


Rick


dragec Mon, 10/06/2008 - 11:03
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hi,


my host admin saw it on host, and it messed up whole routing table on host.

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