John R Levine wrote
Where's 209.240.157.34 ?
Got a spam advertising a web page there, ARIN claims it's not allocated
although all the space around it is. It routes through Tierranet.
TierraNet (ASN 10732) is advertising 209.240.128.0/19, which includes
209.240.157.34 (ns1.netcolony.com). ARIN reports that they've only
been allocated 209.240.128.0/20 and that the other half of the /19
that they're announcing (209.240.144.0/20) is unallocated.
Perhaps ARIN has reserved the entire /19 for TierraNet, but only
actually allocated the lower /20 to them? Perhaps TierraNet is
announcing their /20 as a /19 to get past Sprint's route filters?
-Richard