[aprssig] APRS-IS: frames bypassing server filter

spam8mybrain spam8mybrain at yahoo.com
Mon Jul 13 18:14:38 EDT 2020


The easy solution is: don't set _any_ filters. Filters to the APRS-IS specify additional extra traffic for your station to receive from the Internet, over and above the minimal traffic sent under the assumption you are running a Tx I-gate. Note there is no way to turn off that minimum traffic, as the APRS-IS assumes every client is a Tx I-gate.
    
If you don't want extra traffic, don't ask for it. :-)Andrew, KA2DDOauthor of YAAC (a client program that can ask for additional APRS-IS traffic by default if set up for it)

-------- Original message --------
From: Wojtek SP9WPN <sp9wpn at gmail.com> 
Date: 7/13/20  17:56  (GMT-05:00) 
To: aprssig at lists.tapr.org 
Subject: [aprssig] APRS-IS: frames bypassing server filter 

Hello everybody,I'm running a simple APRS-IS receiver (using direwolf). It uses a metered GSM connection, so I try to control costs by reducing amount of unnecessary or redundant data.As I have no possibility to Tx from this location, it is an obvious step to stop any frames being sent from APRS-IS server to my client (they will never be forwarded to RF). But here the problem appears: I've tried setting different server-side filters without any success. It seems that some frames always reach me despite applied filtering (mostly these are same stations all the time). I've tried different tier2 servers, both aprsc and javAPRS - no difference. This is short sample what I get in logs:[ig>tx] SR9KFZ-2>APRX29,TCPIP*,qAC,T2POLAND:;SQ9RHX *111111z5108.47N/01701.74E-PHG3360 Damian[ig>tx] SR7NSI>BEACON,TCPIP*,qAC,T2POLAND:;438.825-S*121515z5135.96N/01841.68ErC077 -760 SR7SI op SQ7PGP[ig>tx] SR7NSI>APNW01,TCPIP*,qAC,T2POLAND:@121515z5135.60N/01844.02E#432,500MHz op SQ7PGP KZK TEAM[ig>tx] SQ9NKH-9>APK101,SR9POD*,WIDE1*,W2-1,qAR,SR9NSK::SQ7LQU-9 :73!{Q[ig>tx] SQ9NKH-9>PP0PP0,SR9POD*,WIDE1*,W2-1,qAR,SR9NSK:'vX<0x1c>l <0x1c>>/]"3r}op.Lukasz 73![ig>tx] OK8UOF>APMI06,TCPIP*,qAC,T2LONDON::OK8UOF :PARM.Vin,Rx1h,EffTot,Eff1h,Temp,O1,O2,O3,O4,I1,I2,I3,I4I know that my station is supposed to transmit messages to any station which was heard previously, but these are not messages - mostly telemetry and beacons. I can't find any common factor in these frames, but there are not completely random (most of the are from SP, OK, OL, but occasionally some from I or S5 appear, so there's some geographical connection). I've tried to find the reason or rule which causes them to be sent, but no luck. Even on Polish APRS forum people are surprised I'm getting lots of frames having set eg. b/SP9WPN-1 filter.Could somebody with extent knowledge of APRS-IS shed some light on this? Even if I can't ultimately block those frames, it would be great to understand why they are forwarded from server to my station. Right now it's a mystery for me.Best Regards,Wojtek-- 73!Wojtek SP9WPN_______________________________________________aprssig mailing listaprssig at lists.tapr.orghttp://lists.tapr.org/mailman/listinfo/aprssig_lists.tapr.org
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