BCP38 exceptions for RFC1918 space

David Freedman david.freedman at uk.clara.net
Mon Aug 16 05:42:41 CDT 2010


Florian Weimer wrote:
> What's the current consensus on exempting private network space from
> source address validation?  Is it recommended?  Discouraged?
> 
> (One argument in favor of exceptions is that it makes PMTUD work if
> transfer networks use private address space.)
> 
> 

IMHO, operators who number infrastructure out of RFC1918 and then permit
internet traceroutes over it are misguided and should consider avoiding
TTL decrement (i.e using mpls without internet TTL propagation) as a
less stressful (for us) alternative to simply filtering.

Dave.
-- 


David Freedman
Group Network Engineering
Claranet Group





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