There is often confusion when setting up A2Billing about Asterisk Realtime and SIP/IAX2 configuration files. Here’s a quick explanation between the two and some pointers if you have problems.
For a SIP or IAX2 account to be able to connect to Asterisk it needs to be made aware of the SIP/IAX2 account details (username, password, etc). The original way for A2Billing to tell Asterisk about any customers with SIP/IAX2 access details was to create 2 files – additional_a2billing_sip.conf and additional_a2billing_iax.conf. These would then be ‘included’ as part of the Asterisk configuration files so when Asterisk was reloaded the account details were read.
This is pretty straight forward but does have a couple of downsides. Firstly, it’s not dynamic. Asterisk needs to reread the configuration files when any new accounts are added. Secondly, if you have multiple Asterisk/A2Billing servers there is no central repository for these account details.
A more flexible, but slightly more difficult to setup, option is Asterisk Realtime. Asterisk Realtime stores configuration information in a database (such as MySQL). It can store various configuration information in the database but for A2Billing’s purposes we will be storing SIP and IAX2 account details.
Some confusion comes that the default is for Asterisk Realtime to be turned on in A2Billing (at least in 1.8). So SIP/IAX2 accounts will not work until either Realtime is configured in Asterisk, or A2Billing is told to use the configuration file method instead. The setting for this can be found in the A2Billing admin GUI under SYSTEM SETTINGS, Global List, global, Use Real Time.
Information about setting up Asterisk Realtime can be found here –