Setting up ENUM as part of your RTC deployment, in the public ENUM tree, an internal ENUM tree or both, are optional steps that provides more flexibility and resilience for routing calls.
In various countries, it is possible to have your phone
numbers registered in the public ENUM tree for e164.arpa.
Wikipedia maintains a
detailed list of national ENUM registries.
Even if your country does not have a national ENUM scheme yet,
many large organizations are operating an internal ENUM service.
If you have a domain name server, you can create NAPTR
records in the zone files just as easily as creating an A
or CNAME record. It is relatively easy to construct a
script using Python or Java to read from a company telephone directory
and write a zone file for the name server. The file can be regenerated
periodically by a cron job.
If your phone numbers are available in a local LDAP server, the dlz-ldap-enum module can be used in a Bind9 DNS name server to support real-time queries.
Install the package using the appropriate tool, as demonstrated
in Example 15.2, “Installing dlz-ldap-enum on Debian/Ubuntu” and
Example 15.3, “Install dlz-ldap-enum on Fedora/RHEL/CentOS”.
The configuration file is dlz_ldap_enum.conf. On
a Debian/Ubuntu system, it can be found in /etc/bind
while Fedora/RHEL/CentOS users will find it in
/etc/named.
The first step is to customize the file to specify the exact
location of the plugin, the ENUM DNS suffix and your LDAP server
connection parameters, as demonstrated in
Example 15.4, “Sample dlz_ldap_enum.conf”.
Example 15.4. Sample dlz_ldap_enum.conf
dlz "example" {
database "dlopen /usr/lib/dlz-ldap-enum/dlz_ldap_enum.so 2
v3 simple {cn=admin,dc=example,dc=org} {secret} {127.0.0.1}
e164-addr.example.org
{localhost. root.example.org. 2 604800 86400 2419200 604800}
localhost
60
ldap:///ou=$zone$,dc=example,dc=org???objectclass=top
ldap:///dc=example,dc=org?mail?sub?telephoneNumber=$record$";
};
Now add a reference to this file into the main
named.conf, which may be under /etc/bind or
just /etc depending upon your system. This is
demonstrated in
Example 15.5, “Additions to named.conf for Debian/Ubuntu” and
Example 15.6, “Additions to named.conf for Fedora/RHEL/CentOS”.
Example 15.6. Additions to named.conf for Fedora/RHEL/CentOS
include "/etc/named/dlz_ldap_enum.conf";