Asterisk cmd EnumLookup

Synopsis:

Lookup number in ENUM

This command is deprecated in Asterisk 1.4 See Asterisk func enumlookup for the replacement.

Description:

EnumLookup(exten)

Looks up an extension via ENUM and sets the variable ‘ENUM’. The extension needs to include a full international telephone number, including the country code but with no zeros or other characters before the country code, like 46XXXXXXXX_ for a Swedish phone number.

Update Oct. 2005: It appears that Enum now requires a + character at the beginning of the exetension, e.g.: EnumLookup(+${EXTEN})

Return codes

Currently, the enumservices SIP, IAX and TEL are recognized. A good SIP entry will result in normal priority handling, whereas a good TEL entry will increase the priority by 51 (if existing)
If the lookup was not successful and there ex ists a priority n + 101, then that priority will be taken next.

Example

[fullaccess]
exten=> _0[1-9]XXX.,1,BackGround(nic.at/enum-doing)
exten=> _0[1-9]XXX.,2,EnumLookup(+431${EXTEN:1})

${EXTEN

1} is the number dialedby user with the leading 0 stripped.

Thus “431${EXTEN

1}” is the E.164 number.

;EnumLookupsets ${ENUM} on success. On failure jumps to priority+101.
exten=> _0[1-9]XXX.,3,BackGround(nic.at/enum-successful)

exten=> _0[1-9]XXX.,4,Dial(${ENUM},30)
exten=> _0[1-9]XXX.,5,Goto(104); No answer on SIP, fallback to PSTN
exten=> _0[1-9]XXX.,103,BackGround(nic.at/enum-failed)
exten=> _0[1-9]XXX.,104,Dial,${TRUNK}/${EXTEN:1}

For other examples, see Asterisk E164 Call Routing or RFC Compliant ENUM Macro

Please note

• By implementing your local ENUM-alike DNS system to support E.164 reverse phone number lookups in DNS, you disable the possibility to lookup in the global ENUM-tree that is implemented in some countries around the world. To configure ENUM lookup in multiple domains, add your Enum-alike DNS root domain before the Enum designated domain, e164.arpa in Asterisk config enum.conf.
• To get wildcard constructs with regular expression matching working, you need to make sure that you have a recent version of DNS servers, for BIND at least version 9. Otherwise, the slave servers might get a faulty zone, with the “\\” constructs being replaced by a single backslah.
• When returning a TEL uri, EnumLookup only returns the number part of the URI, not the “tel:” prefix. For other URL:s, the prefix is SIP/ etc to make it easier to use the Asterisk cmd Dial application in your dial plan.
• Asterisk only reads the first offered NAPTR pointer, it doesn’t read all of them or use the priority scheme.

See also

• ENUM: The ENUM standard
• enum.conf: Configuration
• Asterisk variables
• NIC.AT presentation on Asterisk and ENUM
• E164.org
• NRenum
• LCDial.sh AGI script: Asterisk AGI script for least cost dialing which also transparently attempts an ENUM lookup

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