Authoritative DNS server for 12.54.94.0/23 PTR

[Mike Gatti <ekim.ittag () gmail com>]

Hello Nanog Members, 

We have been having some issue doing reverse lookups for ip's in the 12.54.94.0/23 prefix. We know that this block is 
assigned to AT&T and AT&T has assigned that block to Siemens Medical (based on whois queries). We are now trying to 
find out who would be the authoritative DNS server that would resolve PTR queries for these IP addresses. Would someone 
from AT&T (or Siemens) or someone that has that info please contact me offline to discuss?

Thanks Everyone, 
--
Michael Gatti  
cell.949.735.5612
ekim.ittag () gmail com
(UTC-8)