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Infrastructure Config, was Re: [aprssig] RE: Not Receiving Messages from APRS-IS (Pete Loveall AE5PL Lists)

Curt, WE7U archer at eskimo.com
Tue May 20 14:41:13 UTC 2008


On Tue, 20 May 2008, Joel Maslak wrote:

> They should generally use the basic IGate algorithm, no white or black lists.
> That is, if the IGate hears a station on RF in the last half hour or so (can't
> remember the exact time), and sees a message on the internet stream with that
> station as a destination, it automatically gates it.

Simpler is better in this case.  Xastir uses a 1 hour timeout for
each station.  If a station has been heard on a local TNC interface
within the last hour and a message (or an ACK) comes along on the
internet for that station, it is automatically gated to RF.

The above happens if and only if the packet going across the
internet has been authenticated as a ham station, which is of course
what the igate operators originally talked about here with their
"white lists" are trying to do.  This is all handled automatically
by the igate software without whitelists though.

Authenticated into the APRS-IS means it'll have "TCPIP" in the path.
If the packet has "TCPXX" in the path instead, it's an
_unauthenticated_ station, and the igate will refuse to gate that
packet to RF unless the operator has specifically authorized packets
from that callsign to be gated to RF via some special configuration
(sometimes done for weather data, etc).

This automatic  method means that packets from anywhere in the world
with access to the APRS-IS will automatically make it to/from a
mobile station that is within range of an igate.  A simple and
somewhat elegant method.

Requiring "white" lists to allow packets to RF defeats the entire
automatic mechanism described above.  Perhaps it's required in some
countries based on their communications regulations?

-- 
Curt, WE7U.				archer at eskimo dot com
http://www.eskimo.com/~archer
  Lotto:  A tax on people who are bad at math. - unknown
Windows:  Microsoft's tax on computer illiterates. - WE7U.
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