The domain module implements checks that based on domain table determine if a host part of a URI is “local” or not. A “local” domain is one that the proxy is responsible for.
The module operates in caching or non-caching mode depending on value of module parameter db_mode. In caching mode it reads the contents of domain table into cache memory when the OpenSER module is loaded. The content can be reloaded via OpenSER MI command domain_reload. In non-caching mode, the module queries all the time the database.
If your SIP server operates many domains, you need this module.