mysidia at gmail.com
Sun Jan 15 02:44:29 CST 2012
On Sun, Jan 15, 2012 at 2:20 AM, Ted Fischer <ted at fred.net> wrote:
> We were supposed to have lit up the last of IPv4 last year. I would have
> presumed that meant that there was nothing left. Since I can't find a
Not a good assumption. There remains IPv4 address space that has not yet
been assigned to any network, but is available for assignment. 172/12
appears to likely fall into that category.
there are - supposedly - no fresh IPv4 addresses left to allocate, and the
> only reference to this block is that 172/8 is allocated to ARIN. It
> doesn't even appear in RFC 5735.
Just because ARIN does not appear to have allocated networks from 172/12
yet does not mean this address space is unavailable, not part of the free
pool, or will not be allocated from by ARIN in the future. Just a /12 is
a very small shard of IP address space.
This is also part of a legacy /8.
My question is about 172/12. Where is it, what is it's supposed purpose.
This falls under IP addresses that can be assigned to networks but have not
yet been recorded as assigned to any networks.
> I'm almost sure it's an internal box. I just find it better to give a
> professional answer to "why can't I use this" than just "you can't use
Only the RFC1918 IP address space is reserved for use by private networks.
172/12 is not reserved by RFC, therefore portions of it that are
be allocated at any time.
this and why is this address scanning you for udp/137 anyway".
Something is generating packets sourced with an IP address in that range
which should not be using that source IP address.
It could be a device misconfiguration, or it could be intentional IP
> If someone can point out to me what was done with 172/12 I'd appreciate it.
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