[Ham-Mac] EchoMac behind a NAT router, with "trigger" port

[Jim Tittsler]

I continue to get mail nearly daily from people behind routers that  
have network address translation (NAT) enabled that are having  
trouble getting EchoMac to work.  The symptom they all report is that  
they will be able to connect to the Echolink servers and see the  
available station list, but not be able to successfully connect to  
another station and exchange audio.

As it says in the Help file, your Mac *must* be able to receive UDP  
packets on ports 5198 and 5199 on your public IP address.  If you are  
behind a router, that usually means setting up "port forwarding" so  
that packets from the Internet on those ports get routed to your  
Mac's private IP address.

Many consumer level routers offer a configuration that watches for  
data on a "trigger" port, and when that is detected, automatically  
set up port forwarding on (other) specified ports.  The D-Link DI-604  
was today's example.
   <http://support.dlink.com/emulators/di604_reve/adv_appl.html>
If you configure it for:
Name: EchoMac
Trigger Port:  5200
Trigger Type:  TCP
Public Port: 5198-5199
Public Type: UDP
The router will watch for your connection to the Echolink servers,  
and when that is detected, automatically configure itself to forward  
the appropriate UDP traffic to your Mac.

Alternatively, you can configure your router to always forward UDP  
traffic on those ports to a specified private IP address.  This can  
be less convenient if your Mac isn't always assigned the same IP  
address, or if you want to use EchoMac/Echolink from more than one  
computer on your LAN at different times.

Also note that the OS X firewall in Tiger can now be configured to  
restrict UDP traffic.  If you have enabled that feature, be sure to  
make an opening for UDP ports 5198 and 5199.

If you continue to have problems, check the Echomac-users mailing  
list archives, or join the list.
   <http://lists.sourceforge.net/mailman/listinfo/echomac-users>

73, Jim

-- 
Jim Tittsler  7J1AJH/AI8A  Tokyo                     GPG: 0x01159DB6
http://www.qsl.net/7j1ajh/                       QRP/Satellites/APRS
Echolink: *TIARA* Conference                            AMSAT/NZART