pop.lx4.zetosa.com.pl has no NS records.
NS records for this zone are defined at lx4.zetosa.com.pl.
NS records for this zone are defined at lx4.zetosa.com.pl.
Question and response
Question
dig mail.lx4.zetosa.com.pl. NS
Answer
The response has no answer records.
Authority
lx4.zetosa.com.pl. 10800 SOA ns1.lx4.zetosa.com.pl. postmaster.lx4.zetosa.com.pl. 2010092900 28800 900 2419200 10800
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0