BCP38 exceptions for RFC1918 space

[marcoh at marcoh.net (Marco Hogewoning)]

On 15 aug 2010, at 20:05, Randy Bush 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.)
> 
> and this is a good thing?  
> 
> rfc1918 packets are not supposed to reach the public internet.  once you
> start accommodating their doing so, the downward slope gets pretty steep
> and does not end in a nice place.


I cannot agree more with this. If you want PMTU use non-private space, there is enough really :) And saving a /24 by renumbering your core into RFC 1918 won't save you from the coming run out.

MarcoH