Asterisk + some modules and ports
By default Asterisk use:
1. TCP:1720 chan_ooh323.so 2. TCP:2000 chan_skinny.so 3. UDP:2727 chan_mgcp.so 4. UDP:4520 pbx_dundi.so 5. UDP:4569 chan_iax2.so 6. UDP:5000 chan_unistim.so 7. TCP:5038 *** (manager.conf) 8. UDP:5060 chan_sip.so
You can disable 1-7 in the modules.conf with command noload => chan_iax2.so and so close opened ports.
traceroute: sendto: Permission denied Asterisk + rules for a firewall