DNS HOWTO : A simple domain. : The reverse zone
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5.3. The reverse zone

Now programs can convert the names in freebsd.bogus to addresses which they can connect to. But also required is a reverse zone, one making DNS able to convert from an address to a name. This name is used by a lot of servers of different kinds (FTP, IRC, WWW and others) to decide if they want to talk to you or not, and if so, maybe even how much priority you should be given. For full access to all services on the Internet a reverse zone is required.

Put this in named.conf:


zone "196.168.192.in-addr.arpa" {
	notify no;
        type master;
        file "192.168.196";
};

This is exactly as with the 0.0.127.in-addr.arpa, and the contents are similar:


$TTL 3D
@	IN	SOA	ns.freebsd.bogus. hostmaster.freebsd.bogus. (
			199802151 ; Serial, todays date + todays serial
			8H	; Refresh
			2H      ; Retry
			4W	; Expire
			1D)	; Minimum TTL
		NS      ns.freebsd.bogus.

1		PTR	gw.freebsd.bogus.
2		PTR	ns.freebsd.bogus.
3		PTR	donald.freebsd.bogus.
4		PTR	mail.freebsd.bogus.
5		PTR	ftp.freebsd.bogus.

Now you restart your named (ndc restart) and examine your work with dig again:


$ dig -x 192.168.196.4 +pfmin
;; res options: init recurs defnam dnsrch
;; got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 8764
;; QUERY: 1, ANSWER: 1, AUTHORITY: 1, ADDITIONAL: 1
;; QUERY SECTION:
;;      4.196.168.192.in-addr.arpa, type = ANY, class = IN

;; ANSWER SECTION:
4.196.168.192.in-addr.arpa.  3D IN PTR  mail.freebsd.bogus.

so, it looks OK, dump the whole thing to examine that too:


dig -x 192.168.196 AXFR

; <<>> DiG 8.2 <<>> -x AXFR 
$ORIGIN 196.168.192.in-addr.arpa.
@                       3D IN SOA       ns.freebsd.bogus. hostmaster.freebsd.bogus. (
                                        199802151       ; serial
                                        8H              ; refresh
                                        2H              ; retry
                                        4W              ; expiry
                                        1D )            ; minimum

                        3D IN NS        ns.freebsd.bogus.
4                       3D IN PTR       mail.freebsd.bogus.
2                       3D IN PTR       ns.freebsd.bogus.
5                       3D IN PTR       ftp.freebsd.bogus.
3                       3D IN PTR       donald.freebsd.bogus.
1                       3D IN PTR       gw.freebsd.bogus.
@                       3D IN SOA       ns.freebsd.bogus. hostmaster.freebsd.bogus. (
                                        199802151       ; serial
                                        8H              ; refresh
                                        2H              ; retry
                                        4W              ; expiry
                                        1D )            ; minimum

;; Received 8 answers (8 records).
;; FROM: lookfar to SERVER: 127.0.0.1
;; WHEN: Sat Dec 16 01:44:03 2000

Looks good! If your output didn't look like that look for error-messages in your syslog, I explained how to do that in the first section under the heading Starting named


DNS HOWTO : A simple domain. : The reverse zone
Previous: Our own domain
Next: Words of caution