reverse dns problems

[ed at alcpress.com]

I'm having problems with my reverse dns. I had my isp (Sprint)
delegate the subnet 208.21.15.128/25 to my server ns1.mfin.com.
I configured the reverse zone file according to RFC2317 and
a similar zone file is working on another system I manage involving
another isp.

It seems to me that the Sprint DNS servers are not configured
correctly but I could be wrong. Sprint's ns1-auth.sprintlink.net
server provides different answers than I expect but I'm fairly
new at classless in-addr.arpa delegation. I'd appreciate it
if more experience people could look at this.

Ed