$ORIGIN 51.10.in-addr.arpa.
51.10.in-addr.arpa. IN SOA @ root 2018060315 3h 15m 1w 1d

233.34 IN PTR aknode23.vran.k2.ericsson.se.
232.34 IN PTR aknode25.vran.k2.ericsson.se.
231.34 IN PTR aknode27.vran.k2.ericsson.se.
230.34 IN PTR aknode29.vran.k2.ericsson.se.
229.34 IN PTR aknode31.vran.k2.ericsson.se.