At 9:42 -0700 6/1/04, Greg Connor wrote:
Publishers SHOULD limit the size of the cidr ranges to no larger than
the ARIN netblock corresponding to the ASN it is in. If the publisher
wishes to allow multiple ASNs to send mail, they should be listed
individually.
--Edward Lewis <edlewis(_at_)arin(_dot_)net> wrote:
To add some clarification - ARIN does not have information relating
address ranges to AS numbers at the granularity you are probably assuming.
E.g., an organization may have AS numbers 68432 and 72293 and address
ranges 298.34.245.0/24 and 312.3.312.0/23. There's no record how the two
ranges are mapped to the autonomous systems. If could be the latter
range is split among the two AS numbers. --
Thanks. Perhaps AS isn't really related to what we want... If the ARIN
response shows the size of the block as ARIN knows it, that should be
enough. I'm pretty sure the block size is in the whois result. Worst
case, look up the first IP and last IP in the MARID range and see if they
are in the same NETBLK handle.
I think I was thinking about AS in order to avoid going to Whois... if the
block info could be extracted from DNS that would be better for performance
reasons. Perhaps looking up the first and last IP in in-addr.arpa to see
if it is delegated to the same place? Or is there a better way to learn
the size of the ARIN block using only DNS queries?
Thanks
gregc
--
Greg Connor <gconnor(_at_)nekodojo(_dot_)org>