uSipServer is a SIP "server" on Android. Simple to use. Works as SIP proxy and registrar. Supports only UDP-SIP. # Ex) use with CSipSimple as dial number "9999". [0] configure properties below. Domain: SIP server domain. Default value is local IP. Local IP: listening address to SIP message. Default value is "0. 0. 0. 0 (any)". Local Port: listening port to SIP message.