knut.work.  3600 IN SOA   ns1.kserver.biz. dns.ahlers.me. 1 7200 900 1209600 86400
knut.work.  3600 IN NS    ns1.kserver.biz.
knut.work.  3600 IN NS    ns2.kserver.biz.
knut.work.  3600 IN NS    ns3.kserver.biz.