I am trying to install Kamailio on Ubuntu 12.04,but hitting the below issue.

root@test:/usr/local# apt-get install kamailio kamailio-mysql-modules kamailio-tls-modules
Reading package lists... Done
Building dependency tree
Reading state information... Done
E: Unable to locate package kamailio
E: Unable to locate package kamailio-mysql-modules
E: Unable to locate package kamailio-tls-modules