OpenSER is primarily used as a SIP proxy and Registrar. However, it can be used in some other applications such as Proxy dispatches, Jabber Gateway, NAT Traversal together with MediaProxy and RTPproxy. It supports IP versions 4 and 6 and is able to serve multiple domains. OpenSER can be executed in Linux, Solaris, and FreeBSD platforms.

OpenSER was created to be a SIP proxy. However, with the addition of new modules, now OpenSER can be used in a several scenarios such as:

Let's see the most common usage scenarios for OpenSER. In all these scenarios OpenSER works like glue that binds all the SIP components together.