DNSBL define IP Range

Question

I'm using bind (named) name server to have a local DNSBL. The problem is, I'm getting 500+ spam mails a day from certain IP blocks and adding all the IPs one by one is an absurd amount of work.

Is it possible to define IP ranges in the zone file and if so, how?

I did google extensively but the DNSBL topic is very underrepresented in the search results.

here's a snippet of the record:

$TTL 1W
@       IN      SOA     localhost. root.localhost.  (
                                      2008122601 ; Serial
                                      28800      ; Refresh
                                      14400      ; Retry
                                      604800     ; Expire - 1 week
                                      86400 )    ; Minimum
@               IN      NS      localhost.
@               IN      A       127.0.0.1

@               IN      AAAA    ::1
;------------------------------------------------------------------
2.0.0.127       IN      A       127.0.0.2
                IN      TXT     "example.com test record"
3.0.0.127       IN      A       127.0.0.3
                IN      TXT     "example.com verified spam source"
10.0.0.127      IN      A       127.0.0.10
                IN      TXT     "example.com confirmed DUL range"
;------------------------------------------------------------------
23.85.173.113   IN      A       127.0.0.3
253.139.2.198   IN      A       127.0.0.3
212.170.54.142  IN      A       127.0.0.3
6.11.28.50      IN      A       127.0.0.3
64.240.56.149   IN      A       127.0.0.3
15.223.225.110  IN      A       127.0.0.3
; etc

If you know DNSBL, you know those IPs are in reverse digit order e.g. 1.2.3.4.localhost. becomes 4.3.2.1.localhost.

So to repeat myself, how, if it's possible at all, do I define an IP range, let's say 1.2.3.0/24?

Answer 1

Yes, you use wildcards.

In the example of 1.2.3.4, you write

*.3.2.1 IN A 127.0.0.3

dig @127.0.0.1 4.3.2.1.localhost found

dig @127.0.0.1 254.3.2.1.localhost found

dig @127.0.0.1 4.4.2.1.localhost not found