Whois 172/12

Keith Medcalf kmedcalf at dessus.com
Sun Jan 15 12:49:22 CST 2012


As port 137 is the Netbios Name Service port are you *sure* this is a port scan and not a windows box (or other OS running NetBIOS crud) that simply has fat-fingered addresses configured?


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> -----Original Message-----
> From: Ted Fischer [mailto:ted at fred.net]
> Sent: Sunday, 15 January, 2012 01:20
> To: nanog at nanog.org
> Subject: Re: Whois 172/12
> 
> Thanks for the replies so far, but not what I was looking for.
> 
> I should have specified that I've done several ns & dig lookups just to
> make sure.
> 
> 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
> reference to 172/12 anywhere, one might be led to presume that it was
> allocated somehow, to someone (perhaps inadvertently not recorded) since
> 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.
> 
> We all know about 172.16/12 - nothing left of that horse but glue.
> 
> My question is about 172/12.  Where is it, what is it's supposed purpose.
> 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
> this and why is this address scanning you for udp/137 anyway".
> 
> If someone can point out to me what was done with 172/12 I'd appreciate it.
> 
> 
> Patrick opined:
> > Read RFC1918.
> 
>   I didn't remember seeing anything about 172/12 in RFC1918.  Looked at it
> again.  Is there something about 172/12 I missed?  Thanks.
> 
> > Likely a machine on his local network (i.e. behind the same NAT box) is
> > hitting him.
> >
> > But that is not guaranteed.  A packet with a source address of 172.0.x.x
> > could be hitting his machine.  Depends on how well you filter.  Many
> > networks only look at destination IP address, source can be anything -
> > spoofed, un-NAT'ed, etc.  He just wouldn't be able to send anything back
> > to it (unless it was on the local LAN, as I mention above).
> >
> > --
> > TTFN,
> > patrick
> >
> >
> > On Jan 15, 2012, at 2:53 AM, Alex Ryu wrote:
> >
> >> As far as I know, 172.0.1.216 is not assigned, yet.
> >>
> >> whois -h whois.arin.net 172.0.1.216
> >> [whois.arin.net]
> >> #
> >> # Query terms are ambiguous.  The query is assumed to be:
> >> #     "n 172.0.1.216"
> >> #
> >> # Use "?" to get help.
> >> #
> >>
> >> No match found for 172.0.1.216.
> >>
> >>
> >>
> >> #
> >> # ARIN WHOIS data and services are subject to the Terms of Use
> >> # available at: https://www.arin.net/whois_tou.html
> >> #
> >>
> >> Also, when you check BGP routing table, it is not routed at all.
> >>
> >> route-server.as3257.net>sh ip bgp 172.0.1.216
> >> % Network not in table
> >> route-server.as3257.net>
> >>
> >> So it seems like forged IP address.
> >>
> >> Alex
> >>
> >>
> >> On Sun, Jan 15, 2012 at 1:37 AM, Ted Fischer <ted at fred.net> wrote:
> >>> Hi all,
> >>>
> >>>   Tearing what's left of my hair out.
> >>>
> >>>   A customer is getting scanned by a host claiming to be "172.0.1.216".
> >>>
> >>>   I know this is bogus, but I want to go back to the customer with as
> >>> much authoritative umph as I can (heaven forbid they just take my
> >>> word).
> >>>
> >>>   I'm pretty sure I read somewhere once that 172/12 was "reserved" or
> >>> something like that.  All I can find now is that 172/8 is "administered
> >>> by
> >>> ARIN".  Lots of information on 172.16/12, but not a peep about
> >>> 172/12.
> >>>
> >>>   If anybody could provide some insight as to the
> >>> allocation/non-allocation of this block, it would be much appreciated.
> >>>
> >>>   Thanks.
> >>>
> >>> Ted Fischer
> >>>
> >>>
> >>>
> >>>
> >>>
> >>>
> >>>
> >>
> >
> >
> >
> 
> 







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