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Configuring dns naptr records – TANDBERG Gatekeeper User Manual

Page 46

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TANDBERG Gatekeeper User Guide

Page 46 of 105

10.3.

Configuring DNS NAPTR Records

ENUM relies on the presence of NAPTR records, as defined by RFC 2915 [7]. This is used to obtain an

H.323 URI from the E.164 number. The record format that the Gatekeeper supports is:

;; order flag preference service regex replacement

IN NAPTR 10 100 "u" "E2U+h323" "!^(.*)$!h323:\[email protected]!" .

where:

order(10)

and

preference(100)

determine the order in which NAPTR records will be processed:

Lowest order first, with lowest preference being processed first in the case of matching order.

flag (u)

determines the interpretation of the other fields in this record. Only the value u is supported.

service

states that this record is intended to describe E.164 to URI conversion for H.323. Its value

must be

E2U+h323

.

regex

describes the conversion from the given E.164 number to an H.323 URI.

!

is a field separator.

The first part:

^(.*)$

represents the entire E.164 number. The second part:

h323:\[email protected]

represents the H.323 URI that will be generated. In the above example the

E.164 number will be concatenated with

@example.com

, e.g.

1234

will be mapped to

[email protected]

.

The last field of the NAPTR record,

replacement

, is not used and should be set to

.

(i.e. the full stop

character).
Once the DNS NAPTR (for the ENUM lookup) and SRV (for the corresponding H.323 URI lookup) are

present, ENUM dialing should be possible. To verify your configuration, use the

locate

command to try

and resolve an E.164 alias.