ftp.lx4.zetosa.com.pl has no NS records.
NS records for this zone are defined at zetosa.com.pl.
NS records for this zone are defined at zetosa.com.pl.
Question and response
Question
dig www.lx4.zetosa.com.pl. NS
Answer
The response has no answer records.
Authority
lx4.zetosa.com.pl. 4819 SOA ns1.lx4.zetosa.com.pl. postmaster.lx4.zetosa.com.pl. 2010092900 28800 900 2419200 10800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0