You are correct in that some ISPs do not reconize ECHOLINK Host, you have to go into your Firewall and router and tell it to allow the ECHOLINK Host, did it to me the 1st time i tried. Go to the TOOLS, then FIREWALL ROUTER TEST, run the test if it is good it will tell you, if no good it will direct you to a HELP area.
When you get ECHOLINK setup, email me and we will coordinate a "TEST" session.
v/r
Bob
W4RAA