On Sun, Jan 15, 2012 at 2:20 AM, Ted Fischer <[email protected]> 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 unallocated could 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 address spoofing. > If someone can point out to me what was done with 172/12 I'd appreciate it. > -- -JH
