posta.eisif.cz has no CNAME records.
Question and response
Question
dig posta.eisif.cz. NS
Answer
The response has no answer records.
Authority
eisif.cz. 3400 SOA hostbase.netforms.cz. admin.netforms.cz. 2026021508 14400 3600 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0