$ORIGIN 10.168.192.in-addr.arpa.
$TTL 86400
@  IN  SOA  ns1.local.  mail.address.with.stop.as.delimiter. (
       2022081801  ; serial
       21600       ; refresh after 6 hours
       3600        ; retry after 1 hour
       604800      ; expire after 1 week
       86400 )     ; minimum TTL of 1 day
;
@      IN  NS     ns1.local.
;
1      IN  PTR    ns1.local.
2      IN  PTR    web.local.
3      IN  PTR    mail.local.
4      IN  PTR    client.local.