http://wiki.freeswitch.org/wiki/Sofia_Configuration_Files#User_Agent_.5Buser... As per the above link, we can change the User Agent String, but I added this param name but does not seem to work. [user@freeswitch autoload_configs]$ vi sofia.conf.xml <configuration name="sofia.conf" description="sofia Endpoint"> <global_settings> <param name="log-level" value="0"/> <!-- <param name="auto-restart" value="false"/> --> <param name="debug-presence" value="0"/> <param name="user-agent-string" value="Test Server"/> </global_settings> <!-- The rabbit hole goes deep. This includes all the profiles in the sip_profiles directory that is up one level from this directory. --> <profiles> <X-PRE-PROCESS cmd="include" data="../sip_profiles/*.xml"/> </profiles> </configuration>