Re: Unicast Reverse Path Forwarding what IPs are dropped

Keti,

You're almost there. Please take a look the following pages:

http://www.cisco.com/web/about/security/intelligence/unicast-rpf.html
* Surprisingly the best (concise) uRPF artcile on cisco.com

http://www.cisco.com/en/US/docs/ios/12_2/security/configuration/guide/scfrpf.html
* Pretty old but still relevant

http://www.ciscopress.com/articles/article.asp?p=174313&seqNum=3

## Sometimes I refer to the uRPFaccess list as "the second chance" - can you
guess why?

HTH
Kambiz Agahian

CCIE Instructor/Consultant
M.Eng Telecom, CCIE# 25341, CCSI# 33326, MCSE, MCSA

On Fri, Aug 13, 2010 at 12:13 AM, selamat pagi <ketimun_at_gmail.com> wrote:

> According to the docu 4 types of addresses are blocked:
>
> http://www.cisco.com/en/US/docs/ios/12_2t/12_2t13/feature/guide/ft_urpf.html
>
> Loose mode allows Unicast RPF to automatically detect and drop packets such
> as the following:
>
> IETF RFC 1918 source addresses
>
> Other Documenting Special Use Addresses (DUSA) that should not appear in
> the source
>
> Unallocated addresses that have not been allocated by the Regional
> Internet
> Registries (RIRs)
>
> Source addresses that are routed to a null interface on the router
>
> 1) RFC1918 and 4) null route are easy to understand.
>
> But what other address-ranges are blocked ?
>
> Is there a command to show this on the router ?
>
> Many thanks,
> keti
>
>
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Received on Fri Aug 13 2010 - 01:53:14 ART