undefined.hostname.localhost.
Question and response
Question
dig cgnat-hmo-01-35.lixer.net.mx. PTR
Answer
cgnat-hmo-01-35.lixer.net.mx. 5 PTR undefined.hostname.localhost.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0