Reverse DNS Template Reference
Substitution pattern | Example expansion using 192.168.23.45 | |
Whole-IP patterns | ||
Dashed IP | %i | 192-168-23-45 |
Reverse dashed IP | %r | 45-23-168-192 |
Hex-coded IP | %h | c0a8172d |
Decimal IP | %d | 323241453 |
%i and %r also allow explicitly defining the separator; eg %.i or %_r. Dot/period (.), dash (-), and underscore (_) are the only characters supported since DNS names may not contain most other non-alphanumerics. | ||
%blank% may be used to specifically prevent template expansion on a segment of a block if desired; eg, if 192.168.23.0/24 has "unused-%i.example.com" set, adding an A+PTR template for 192.168.23.48/30 of "%blank%" will leave 192.168.23.48 through .51 without PTR records unless specific entries exist for those IPs. | ||
Per-octet patterns (1, 2, 3, or 4 specify the octet; d, h or 0 specify decimal, hexidecimal, or 0-padded decimal) | ||
First octet, decimal | %1d | 192 |
Third octet, 0-padded | %30 | 023 |
Fourth octet, hexidecimal | %4h | 2d |
All octets, different expansions | %1h-%2d-%30-%4h | c0-168-023-2d |
Extensions | ||
Substitution pattern | Example expansion using 192.168.23.40/29 | |
Network/ gateway/ broadcast |
%ngb% |
customer-%i%ngb%.example.com 192.168.23.40 -> customer-net.example.com 192.168.23.41 -> customer-gw.example.com 192.168.23.42 -> customer-192-168-23-42.example.com 192.168.23.43 -> customer-192-168-23-43.example.com 192.168.23.44 -> customer-192-168-23-44.example.com 192.168.23.45 -> customer-192-168-23-45.example.com 192.168.23.46 -> customer-192-168-23-46.example.com 192.168.23.47 -> customer-bcast.example.com |
Any IP pattern component is blanked on the network, gateway, and broadcast IPs when this is
used. Each of n, g, or b can be prefixed with a dash, eg %-ng-b% or %n-g-b%, which will blank that entire entry instead of substituting net, gw, or bcast. |
||
n'th usable IP | %c |
customer-%3d-%c.example.com 192.168.23.40 -> customer-23.example.com 192.168.23.41 -> customer-23.example.com 192.168.23.42 -> customer-23-1.example.com 192.168.23.43 -> customer-23-2.example.com 192.168.23.44 -> customer-23-3.example.com 192.168.23.45 -> customer-23-4.example.com 192.168.23.46 -> customer-23-5.example.com 192.168.23.47 -> customer-23.example.com |
c can be prefixed with a dash (%-c), which starts the numbering from the conventional gateway IP instead. (.41 above would be 1, .42 2, etc, finishing with 6 at .46). |