dnscontrol/docs/_functions/global/REV.md

name	parameters
REV	address

REV returns the reverse lookup domain for an IP network. For example REV('1.2.3.0/24') returns 3.2.1.in-addr.arpa. and REV('2001:db8:302::/48) returns 2.0.3.0.8.b.d.0.1.0.0.2.ip6.arpa.. This is used in D() functions to create reverse DNS (PTR) zones.

This is a convenience function. You could specify D('3.2.1.in-addr.arpa, ...` if you like to do things manually and permit typos to creep in.

The network portion of the IP address (/24) must always be specified.

Note that the lower bits are zeroed out automatically. Thus, REV('1.2.3.4/24') is the same as REV('1.2.3.0/24')`. This may generate warnings or errors in the future.

{% include startExample.html %} {% highlight js %} D(REV('1.2.3.0/24'), REGISTRAR, DnsProvider(BIND), PTR("1", 'foo.example.com.'), PTR("2", 'bar.example.com.'), PTR("3", 'baz.example.com.'), // These take advantage of DNSControl's ability to generate the right name: PTR("1.2.3.10", 'ten.example.com.'), );

D(REV('2001:db8:302::/48'), REGISTRAR, DnsProvider(BIND), PTR("1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0", 'foo.example.com.'), // 2001:db8:302::1 // These take advantage of DNSControl's ability to generate the right name: PTR("2001:db8:302::2", 'two.example.com.'), // 2.0.0. etc. etc. PTR("2001:db8:302::3", 'three.example.com.'), // );

{%endhighlight%} {% include endExample.html %}

In the future we plan on adding a flag to A() which will insert the correct PTR() record if the approprate D(REV() domain (i.e. .arpa domain) has been defined.