OPT-OUT.TXT OPT-OUT CONSIDERATIONS in APRS =========================================================================== Document version: 8.4.7 Document dated: 1 Sept 200 Author(s): Bob Bruninga, WB4APR ABSTRACT AEA.TXT OPT-OUT issues and details ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Ever since I came up with the APRS idea, there has always been concern expressed by a minority over the "Big Brother" issue of letting everyone anywhere see what you are doing on APRS. This issue was magnified to explosive magnitudes with the integration of APRS to the internet. Although there is no such thing as privacy on Amateur radio, there has always been the idea of using the minimum power to get the message across. Also, hams frequently switch to simplex to pass somewhat sensitive information where the reduction in range is on the order of 10 to one resulting in a capture area reduction of 100 to 1. When Steve Dimse implemented FINDU.COM which then began archiving every packet heard on APRS worldwide for permanent archiving and retrieval by anyone at any time, this issue of "Big Brother" or the PUBLIC nature of amateur radio communications rose again. For the sake of the loud minority and to avoid continuous debate over the issue, he allowed for an OPT-OUT mechanism so that users could indicate in their packets that they did not desire their packets to be permanently archived. This is done with a "!x!" in the packet text or by the use of the "X" overlay character in position packets. This then lead the debate over to whether the users should be able to also OPT-OUT of the Internet completely, so that they could indicate that they did not want their packets to be distributed worldwide if they wanted to. Since everything on HAM radio is public, there are very strong opinions on either side of the debate. The proposal was for all IGates to ignore any packet with "NOGATE" in its path. This solution is backwards compatible to all user software and hardware, but needs to be implemented at the IGates to be effective. There seems to be no consensus at hand, and unless/until the IGate authors agree to honor the NOGATE requests, there will probably be no near term OPT-OUT option implemented at the IGates. Rather than take sides, it seems to me that it is simply a matter of choice. SO to allow that small minority that wants to OPT-OUT of the IGates, I have added an OPT-OUT mechanism in APRSdos if they want to use it. The OPT-OUT in APRSdos takes advantage of a weakness in the IGate implementation that uses the presence of the "3rd party" format in a LOOP-CHECK algorithm to eliminate Igate-to-RF-to-IGate loops. While the proper IGate loop-filter should have been implemented around checking for the presence of the "TCPIP" or "TCPxx" path in all headers, it wasnt, and that argument is beyond the scope of this file. THus if a user wants to OPT-OUT of the entire IGate system, then he simply needs to transmit his packets in the 3rd party format, and the IGates will ignore him. So, to place your packets in APRSdos format. Simply toggle on the alt-SETUP-FORMATS-OPT-OUT command. ALso notice that all APRSdos ZIP-LAN packets have always been in 3rd party and are therefore always ignored by the Igates (This is why I am opposed to 3rd party format being the LOOP filter mechanism!)... bob