I have a client that I am hosting DNS for and their ISP delegated part of a /24 block to my dns servers for reverse dns. So basically I have a block of x.x.x.64/27 delegated to my dns servers. I'm not sure of the syntax for the zone for a partial block. I did setup a full block for the full /24 block and locally reverse dns works for the IP addresses in question. However, inbound queries seem to fail since various tests (aol in particular) still fail externally. My problem, of course, is that most of the major ISPs will not accept mail from the locally hosted email server because the reverse dns query is failing.
Anyone have the syntax for a CIDR partial block reverse zone?