Cisco Cisco Expressway Maintenance Manual
(Maintenance > Tools >
Locate) to try to resolve an E.164 alias.
ENUM dialing for incoming calls
For endpoints to be reached using ENUM dialing, you must configure a DNS NAPTR record that maps your endpoints’
E.164 numbers to their SIP/H.323 URIs. This record must be located at an appropriate DNS domain where it can be
found by any systems attempting to reach you by using ENUM dialing.
E.164 numbers to their SIP/H.323 URIs. This record must be located at an appropriate DNS domain where it can be
found by any systems attempting to reach you by using ENUM dialing.
About DNS domains for ENUM
ENUM relies on the presence of NAPTR records to provide the mapping between E.164 numbers and their SIP/H.323
URIs.
URIs.
, which is part of a suite of documents that define the ENUM standard, specifies that the domain for ENUM -
where the NAPTR records should be located for public ENUM deployments - is
e164.arpa
. However, use of this
domain requires that your E.164 numbers are assigned by an appropriate national regulatory body. Not all countries
are yet participating in ENUM, so you may want to use an alternative domain for your NAPTR records. This domain
could reside within your corporate network (for internal use of ENUM) or it could use a public ENUM database such as
are yet participating in ENUM, so you may want to use an alternative domain for your NAPTR records. This domain
could reside within your corporate network (for internal use of ENUM) or it could use a public ENUM database such as
http://www.e164.org
.
Configuring DNS NAPTR records
. These are used to obtain an H.323 or SIP
URI from an E.164 number.
The record format that the Expressway supports is:
order flag preference service regex replacement
where:
■
order
and
preference
determine the order in which NAPTR records are processed. The record with the lowest
order is processed first, with those with the lowest preference being processed first in the case of matching
order.
order.
■
flag
determines the interpretation of the other fields in this record. Only the value
u
(indicating that this is a
terminal rule) is currently supported, and this is mandatory.
■
service
states whether this record is intended to describe E.164 to URI conversion for H.323 or for SIP. Its
value must be either
E2U+h323
or
E2U+SIP
.
■
regex
is a regular expression that describes the conversion from the given E.164 number to an H.323 or SIP
URI.
■
replacement
is not currently used by the Expressway and should be set to
.
(the full stop character).
Non-terminal rules in ENUM are not currently supported by the Expressway. For more information on these, see
section 2.4.1 of
section 2.4.1 of
For example, the record:
IN NAPTR 10 100 "u" "E2U+h323" "!^(.*)$!h323:\1@example.com!" .
would be interpreted as follows:
■
10
is the
order
■
100
is the
preference
■
u
is the
flag
■
E2U+h323
states that this record is for an H.323 URI
155
Cisco Expressway Administrator Guide
Dial Plan and Call Processing