Whois 172/12

Jeroen Massar jeroen at unfix.org
Sun Jan 15 08:43:46 UTC 2012

On 15 Jan 2012, at 09:20, "Ted Fischer" <ted at fred.net> wrote:
> My question is about 172/12.  Where is it, what is it's supposed purpose. 

See IANA which tells you at 

That ARIN is handling it. As their whois does not have anything for it, and BGP does not have it it obviously is unused as of yet and somebody is just spoofing. Solution: implement BCP38 in your network.

Note that IANA has run out of v4, the RIRs themselves have quite a bit left, obviously, ARIN still has big chunks of 172/8.

> I'm almost sure it's an internal box.

Then apply BCP38 and figure out where it lives.

>  I just find it better to give a
> professional answer to "why can't I use this" than just "you can't use
> this and why is this address scanning you for udp/137 anyway"

It is not their address space, as such they are not supposed to use it. What is so difficult about that answer?!


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