I have asterisk working great on my LAN but cannot open the necessary RTP ports on my ISA firewall server to get to the outside world. (I must open each port manually). Idealy, I would like to reduce the number of RTP ports in use.
I noticed in rtp.conf that I can limit the range of RTP ports. So:
- How many ports will I need for a home with 3 phones (and two external phone “lines”).
- If I restrict the RTP port range to 10000-10005, does this mean that my asterisk server will only use these RTP ports for outgoing, but an external host may still try to contact my server on any port between 10000-20000 if the call is initiated externally?