The IP Database can pass reverse DNS information back and forth to a DNS management backend to simplify maintenance of the reverse DNS records associated with the IPs being managed.
Several shortcuts can be used when specifying a pattern for an IPv4 netblock, which will be expanded to actual DNS records by the DNS management system.
Entries should generally only be present in the "Per-IP reverse entries" section if they are different from the block pattern.
Template patterns are not supported for IPv6 allocations due to the size of the address space and typical size of allocations.
"(cached)" or "[local]" indicates the rDNS information shown came from IPDB records, and not the DNS management utility. It may be out of date, or DNS management integration may be missing or incomplete for this block.
| Whole-IP patterns | ||
| Substitution pattern | Example expansion using 192.168.23.45 | |
| 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). | ||