$ORIGIN 31.172.in-addr.arpa. $TTL 86400 @ 1D IN SOA ns1.wLeiden.NET. hostmaster.wLeiden.NET. ( 20031025 ; serial (d. adams) 3H ; refresh 15M ; retry 1W ; expiry 1D ) ; minimum $INCLUDE wleiden/ns-172 @ 0.0 PTR network.wLeiden.NET. 1.255 PTR proxy.wleiden.net. 2.255 PTR link2proxy.wleiden.net. 3.255 PTR link3proxy.wleiden.net. 4.255 PTR link4proxy.wleiden.net.