IPv6 Netowrk Device Numbering BP

Fri Nov 2 09:52:22 UTC 2012

* Owen DeLong

> Yes, it was pointed out to me that for some silly reason passing
> understanding, that syntax is supported. It's absurd, but supported.
> Sigh
> 
> Probably we should deprecate it as it really doesn't make sense to 
> use it that way.

It absolutely does make sense, especially in the case of IPv4/IPv6
translation. For example, when using NAT64, "64:ff9b::192.0.2.33" is an
example of a valid IPv6 address that maps to 192.0.2.33. Much easier to
relate to for a human than "64:ff9b::c000:221" is.

Similarly, when using SIIT, the same syntax may be used in firewall
rules or ACLs. So if you want to open, say, the SSH port from a trusted
IPv4 address 192.0.2.33 on the far side of the SIIT gateway to your IPv6
server, it's much easier to open for "64:ff9b::192.0.2.33", and it will
also make your ACL much more readable to the next guy that comes along
than if you had used "64:ff9b::c000:221".

Also see RFC 6052 section 2.4.

-- 
Tore Anderson
Redpill Linpro AS - http://www.redpill-linpro.com/