====== Writing Reverse Zone For IPv6 addresses ======

===== Bind8/9 zonefile =====

**Example subnet**
<code bind|f 2001:15c0:66e9>
;
; 2001:15c0:66e9::/48
;
$TTL 3d	; Default TTL (bind 8 needs this, bind 9 ignores it)
$ORIGIN 9.e.6.6.0.c.5.1.1.0.0.2.ip6.arpa.
@	IN SOA ns.xxxxx.tld. hostmaster.xxxxx.tld. (
		2009050120	; Serial number (YYYYMMdd)
		24h		; Refresh time
		30m		; Retry time
		1w		; Expire time
		3d		; Default TTL (bind 8 ignores this, bind 9 needs it)
)

                                ; Name server entries
                 IN     NS     ns.xxxxx.tld.
                 IN     NS     ns2.xxxxx.tld.
                 IN     TXT	"2001:15c0:66e9::/48 Example IPv6 reverse"
; IPv6 PTR entries

; Subnet #1
$ORIGIN 1.0.0.0.9.e.6.6.0.c.5.1.1.0.0.2.ip6.arpa.

1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0         IN      PTR     foobar.xxxx.tld.

; Subnet #2
$ORIGIN 0.0.0.0.9.e.6.6.0.c.5.1.1.0.0.2.ip6.arpa.

1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0         IN      PTR     gw.xxxxxx.tld.

</code>

<code bind|f named.arpa.zone.conf>
zone "9.e.6.6.0.c.5.1.1.0.0.2.ip6.arpa" {
	notify yes;
	type master;
	file "/etc/bind/arpa/2001:15c0:66e9";
        allow-update { none; };
        allow-transfer {xxxx};
};
</code>

===== PTR calculation =====

**Easy was for writting PTR records**
   * Using **ipv6calc**
<code>
$ ipv6calc 2001:15c0:66e9::1 --out revnibbles.arpa
No input type specified, try autodetection...found type: ipv6addr
1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.9.e.6.6.0.c.5.1.1.0.0.2.ip6.arpa.
</code>
   * Using **perl**
<code>
$ perl -e 'use Net::IP;$ip=new Net::IP("2a02:c0:100::2/128");print ($ip->reverse_ip()."\n");'
2.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.1.0.0.c.0.0.2.0.a.2.ip6.arpa.
</code>
   * Using **sipcalc**
<code>
$ sipcalc -r 2a01:c08::14
-[ipv6 : 2a01:c08::14] - 0

[IPV6 DNS]
Reverse DNS (ip6.arpa)  -
4.1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.8.0.c.0.1.0.a.2.ip6.arpa.
</code>