Cisco uRPF failures

Jo Rhett jrhett at
Thu Sep 11 12:26:54 CDT 2008

On Sep 11, 2008, at 10:11 AM, Saku Ytti wrote:

> On (2008-09-11 00:50 -0700), Jo Rhett wrote:
>> As someone who does a lot of work talking to NOCs trying to chase  
>> down
>> attack sources, I can honestly tell you that I haven't talked to a
>> single NOC in the last 16 months who had BCP38 on every port, or  
>> even on
>> most of their ports.  And the majority response is "our (vendor) gear
>> can't handle it".   As we both know, Cisco is the largest by far  
>> vendor
>> in the marketplace, and I've heard that name more than 70% of the  
>> time.
> Sound like these shops are using 3550 as router, which is common for
> smaller shops, especially in EU. And indeed, 3550 would not do uRPF.
> (3560E does).

I don't honestly know.  I do know that in every case it was mentioned  
to me it was either a 6500 or a 7600.
(that it was a Cisco anyway)

But frankly, lack of uRPF doesn't mean that BCP38 is impossible.  My  
generation of Force10 gear can't do uRPF.  Yet we are BCP38 compliant.

Jo Rhett
Net Consonance : consonant endings by net philanthropy, open source  
and other randomness

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