For SIP registration and proxy, Enswitch one of:

• OpenSIPS. This is the default for systems installed using version 2.11 or later. Its configuration is held in the Enswitch database, and you should use the steps on this page to configure call routing. You should add a machine for every machine OpenSIPS may exchange calls with, including the OpenSIPS machine's own main IP address (for enswitch_sipd). Other machines in the cluster need not be added, but can be for reference purposes.
• OpenSER. This is the default for systems installed using versions 2.7 to 2.10. OpenSER is the old name for OpenSIPS, and behaves the same way.
• SER. This is the default for systems installed using version 2.6 or earlier, though such systems may have since been upgraded. Its configuration is in text files, and the steps on this page are irrelevant. Any machines configured via the web interface will be ignored.

To configure the list of machines for OpenSIPS

1. Log in to the Enswitch web interface.
2. Go to System » Machines.
3. Click the "New" button.
4. Enter the following:
• The host name, excluding the DNS domain. For example, enter "asterisk1" rather than "asterisk1.example.com".
• The DNS domain, for example "example.com".
• Optionally a description.
• The IP address for SIP. Use the public IP address rather than "127.0.0.1".
• Whether to send calls to Asterisk on this machine for onward routing. Use "no" for machines which run Asterisk, but which OpenSIPS should not try sending calls to.
• The port to send SIP calls to. If Asterisk is running on the same machine as OpenSIPS, this is normally 5070. If not, this is normally 5060.
5. Click the "Save" button.
6. Repeat for any other machines in the cluster that OpenSIPS may exchange calls with, including itself.
7. Optionally repeat for all other machines in the cluster.