[c-nsp] IOS - ipv6 uppercase in config - why ?

Nick Hilliard nick at foobar.org
Wed Jan 5 13:31:45 EST 2011


On 05/01/2011 16:01, Brandon Applegate wrote:
> Is there a reason that ipv6 addresses are stored with uppercase letters
> in config ?

yes.  See rfc4291, section 2.2, where all of the examples are in upper 
case.  These examples caused people to prefer upper case notation for ipv6 
address representation, although there was actually nothing in the document 
which actually mandated the use of upper case.

These recommendations have been updated in rfc5952, which requires (i.e. 
MUST) that all ipv6 addresses be represented in lower case.  This document 
is standards track, so I guess Cisco is going to have to change at some 
stage.  Given the current low levels of ipv6 deployment, sooner would be a 
lot less painful than later.

Nick



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