How to Sniff Packets Going to a Single Host?

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ch...@chrismaness.com

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Apr 26, 2020, 6:33:36 PM4/26/20
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Ok, in my effort to trouble shoot the hit/miss issue of my server.  I am

now suspecting that the packets that it passes are sometimes malformed. 
Unless other people have issues with their packets not showing up.  I
would like to record whole packets going to cwop.aprs.net:23 and only
those packets.  What command can I use to capture the all of the packets
with all of their payloads?


Thanks,

Chris KQ6UP
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gjr80

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Apr 26, 2020, 6:45:51 PM4/26/20
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You already have it in your log:

Apr 26 14:10:27 raspberrypi weewx[12666]: restx: CWOP: packet: KQ6UP>APRS,TCPIP*:@262110z3401.26N/11718.84W_241/007g017t098r000p000P000b10150h22L774.weewx-3.9.2-Interceptor#015
Apr 26 14:10:28 raspberrypi weewx[12666]: restx: CWOP: Connected to server cwop.aprs.net:23

ch...@chrismaness.com

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Apr 26, 2020, 6:58:37 PM4/26/20
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On 4/26/20 3:45 PM, gjr80 wrote:
You already have it in your log:

Apr 26 14:10:27 raspberrypi weewx[12666]: restx: CWOP: packet: KQ6UP>APRS,TCPIP*:@262110z3401.26N/11718.84W_241/007g017t098r000p000P000b10150h22L774.weewx-3.9.2-Interceptor#015
Apr 26 14:10:28 raspberrypi weewx[12666]: restx: CWOP: Connected to server cwop.aprs.net:23

Could you look over those and see if they are malformed?  Not sure why the always seemed to get accepted, but don't wind up on Findu-> KQ6UP.  I have several successfully posted for the past hour using the single server cwop.aprs.net:23.  Let's cross our fingers and hope it keeps it up.  However, it is not very satisfying to never figure out what was actually messing up.

Thanks,

Chris KQ6UP

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Chris Maness

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Apr 26, 2020, 7:13:17 PM4/26/20
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-----BEGIN PGP SIGNED MESSAGE-----

Hash: SHA256


Poop, 16:00 did not post.  Here is the packet.  Any issues with it?


Apr 26 16:00:16 raspberrypi weewx[12666]: restx: CWOP: packet: KQ6UP>APRS,TCPIP*:@262300z3401.26N/11718.84W_313/007g015t096r000p000P000b10143h24L488.weewx-3.9.2-Interceptor#015


Chris KQ6UP

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ch...@chrismaness.com

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Apr 26, 2020, 7:17:00 PM4/26/20
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On 4/26/20 4:13 PM, Chris Maness wrote:
>
> Hash: SHA256
>
>
> Poop, 16:00 did not post.  Here is the packet.  Any issues with it?
>
>
> Apr 26 16:00:16 raspberrypi weewx[12666]: restx: CWOP: packet:
> KQ6UP>APRS,TCPIP*:@262300z3401.26N/11718.84W_313/007g015t096r000p000P000b10143h24L488.weewx-3.9.2-Interceptor#015
>
>
> Chris KQ6UP
>
I should say they posted, but did not show up on the APRS network (findu
or APRS.fi).

Chris KQ6UP

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Tom Keffer

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Apr 26, 2020, 7:26:28 PM4/26/20
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Looks normal to me.

Chris: the CWOP code has been working for over 10 years on thousands of stations worldwide. It's possible there is an issue with it, but very unlikely.

Far more likely is that you have a network configuration issue. Does your router allow port 14580 to pass?

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ch...@chrismaness.com

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Apr 26, 2020, 7:46:43 PM4/26/20
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On 4/26/20 4:25 PM, Tom Keffer wrote:
> Looks normal to me.
>
> Chris: the CWOP code has been working for over 10 years on thousands
of stations worldwide. It's possible there is an issue with it, but very
unlikely.
>
> Far more likely is that you have a network configuration issue. Does
your router allow port 14580 to pass?

Yes, I tested it with the telnet command.  It connected to 14580 just
fine.  This Raspberry PI tends to have weird connectivity issues if I
use it like a hotspot.  I see my packet does not show up if there are
any timeout warnings.  The odd thing is it seems to make it on the
retry, but if my there was a retry the packet never shows up on APRS.fi
or findu.  Here is some log data:

chris@raspberrypi:~ $ sudo tail -f /var/log/syslog | grep CWOP
Apr 26 16:25:23 raspberrypi weewx[12666]: restx: CWOP: wait interval
(300 < 600) has not passed for record 2020-04-26 16:25:00 PDT (1587943500)
Apr 26 16:30:19 raspberrypi weewx[12666]: restx: CWOP: packet:
KQ6UP>APRS,TCPIP*:@262330z3401.26N/11718.84W_287/007g021t094r000p000P000b10139h24L455.weewx-3.9.2-Interceptor#015
Apr 26 16:30:39 raspberrypi weewx[12666]: restx: CWOP: Attempt 1 to
cwop.aprs.net:23. Connection error: timed out
Apr 26 16:30:39 raspberrypi weewx[12666]: restx: CWOP: Connected to
server cwop.aprs.net:23
Apr 26 16:31:00 raspberrypi weewx[12666]: restx: CWOP: Exception <class
'socket.timeout'> (timed out) when looking for response to packet packet
Apr 26 16:31:00 raspberrypi weewx[12666]: restx: CWOP: Published record
2020-04-26 16:30:00 PDT (1587943800)
Apr 26 16:35:25 raspberrypi weewx[12666]: restx: CWOP: wait interval
(300 < 600) has not passed for record 2020-04-26 16:35:00 PDT (1587944100)
Apr 26 16:40:31 raspberrypi weewx[12666]: restx: CWOP: packet:
KQ6UP>APRS,TCPIP*:@262340z3401.26N/11718.84W_265/008g019t094r000p000P000b10140h23L404.weewx-3.9.2-Interceptor#015
Apr 26 16:40:31 raspberrypi weewx[12666]: restx: CWOP: Connected to
server cwop.aprs.net:23
Apr 26 16:40:51 raspberrypi weewx[12666]: restx: CWOP: Exception <class
'socket.timeout'> (timed out) when looking for response to packet packet
Apr 26 16:40:51 raspberrypi weewx[12666]: restx: CWOP: Published record
2020-04-26 16:40:00 PDT (1587944400)

All these packets are no shows, but if it works on the first go it does
show up.  I had 6 go through in a row, and now these fails.  I wonder if
the PI itself has issues with overheating or something.  When I use it
as a hotspot, it seems fine at first, but then gets crappy and slow
connections.  However, there seems to be an issue with WeeWx or CWOP
re-negotiating connections if the first attempt fails.


Thanks,

Chris KQ6UP

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Greg Troxel

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Apr 26, 2020, 8:05:10 PM4/26/20
to ch...@chrismaness.com, weewx...@googlegroups.com
ch...@chrismaness.com writes:

> All these packets are no shows, but if it works on the first go it does
> show up.  I had 6 go through in a row, and now these fails.  I wonder if
> the PI itself has issues with overheating or something.  When I use it
> as a hotspot, it seems fine at first, but then gets crappy and slow
> connections.  However, there seems to be an issue with WeeWx or CWOP
> re-negotiating connections if the first attempt fails.

I would suggest using tcpdump with the -w option to save a trace, and
then go back over the data to analyze the messages, particularly the
ones that didn't make it. Just run tcpdump with -w, no filters,
because half the point is to see the packets you don't know you are
looking for.

John Ronan

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Apr 27, 2020, 4:03:39 AM4/27/20
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Morning,

Apologies, I'm only catching up on posts now

A few days go I noticed that not all CWOP servers are accepting data. I
haven't heard that the issue has been resolved.

I don't have a list to hand, but I'll try and find it.

cwop.ei3rcw.ampr.org is accepting data, you might try testing only on
that one to rule it out.

Cheers

John

EI7IG


On 4/27/20 00:25, Tom Keffer wrote:
> Looks normal to me.
>
> Chris: the CWOP code has been working for over 10 years on thousands
of stations worldwide. It's possible there is an issue with it, but very
unlikely.
>
> Far more likely is that you have a network configuration issue. Does
your router allow port 14580 to pass?
>
> On Sun, Apr 26, 2020 at 4:13 PM Chris Maness
<christoph...@gmail.com <mailto:christoph...@gmail.com>> wrote:
>
> Hash: SHA256
>
>
> Poop, 16:00 did not post.  Here is the packet.  Any issues with it?
>
>
> Apr 26 16:00:16 raspberrypi weewx[12666]: restx: CWOP: packet:
> KQ6UP>APRS,TCPIP*:@262300z3401.26N/11718.84W_313/007g015t096r000p000P000b10143h24L488.weewx-3.9.2-Interceptor#015
>
>
> Chris KQ6UP
>
>
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ch...@chrismaness.com

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Apr 27, 2020, 9:20:43 AM4/27/20
to weewx...@googlegroups.com, John Ronan

On 4/27/20 1:03 AM, John Ronan wrote:
> Morning,
>
> Apologies, I'm only catching up on posts now
>
> A few days go I noticed that not all CWOP servers are accepting data. I
> haven't heard that the issue has been resolved.
>
> I don't have a list to hand, but I'll try and find it.
>
> cwop.ei3rcw.ampr.org is accepting data, you might try testing only on
> that one to rule it out.
>
> Cheers
>
> John
>
> EI7IG

That would definitely explain it.  Because as far as I can tell all my
posts have been successful, but not all of my packets make it out on the
APRS net.  Also, I have noticed all of the hostnames that I have tried
use round robin DNS to distribute the load, but a handful of CWOP-*
servers are represented in the data.  For example, I might see CWOP-7
and CWOP-3, but other numbers are missing.  That does kind of lead me to
believe that maybe some servers are accepting my posts, but not in turn
relaying them correctly to the APRS network.  I would imagine that
anyone putting their data on the net via inet APRS gateways would be
having the same snaggle tooth data unless they are accessing one known
good server.  I did edit my .conf to only access the ei3rcw node.  Let's
see what happens.  Worst case I can set up a radio packet node.  I do
have a radio and TNC, but I am using it for a PBBS.

Thank you,

Chris KQ6UP

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ch...@chrismaness.com

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Apr 27, 2020, 1:41:24 PM4/27/20
to John Ronan, gjr80, Dave Webb KB1PVH, weewx-user

On 4/27/20 1:03 AM, John Ronan wrote:
> A few days go I noticed that not all CWOP servers are accepting data. I
> haven't heard that the issue has been resolved.
I think some are accepting data, but fail to pass it along.
>
> I don't have a list to hand, but I'll try and find it.
>
> cwop.ei3rcw.ampr.org is accepting data, you might try testing only on
> that one to rule it out.
I ended up using cwop2.mesowest.org as it is not round robin DNS and
resolves to one IP.  I have had 100% successful published packets for a
few hours.
>
> Cheers
>
> John
>
> EI7IG

So thanks.  I guess there was no problem on my end after all.  That is
unless some gates are tolerating some error in formatting that I have
and others are not.  I don't think that is the case though.  Is there a
CWOP/APRS list I can report these issues?


Thanks,

Chris KQ6UP

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John Kline

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Apr 27, 2020, 1:50:46 PM4/27/20
to weewx...@googlegroups.com, John Ronan, gjr80, Dave Webb KB1PVH
Is there a CWOP/APRS list I can report these issues?

You could try here:

I haven’t read through this whole thread, so perhaps you’ve mentioned this, but are you seeing your packets on MesoWest?

For instance, mine are here:

Christopher Maness

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Apr 27, 2020, 1:58:38 PM4/27/20
to weewx...@googlegroups.com, John Kline, John Ronan, gjr80, Dave Webb KB1PVH


On 4/27/20 10:50 AM, John Kline wrote:
Is there a CWOP/APRS list I can report these issues?

ok


I haven’t read through this whole thread, so perhaps you’ve mentioned this, but are you seeing your packets on MesoWest?

For instance, mine are here:


No, but my wind does not pass muster with QC, and don't currently have the means to mount it 10m above any building because my wife would poop on that idea.  I could maybe relocate my station at the local FD or something.

All the packets are now showing up at FINDU now.  They are not missing a beat since I singled out one known good server.

Thanks,

Chris KQ6UP

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jpronans

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Apr 27, 2020, 2:06:04 PM4/27/20
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I reported it to one of the Sysops, but I understand remote access is problematic in the current environment.

Regards,
John
EI7IG 


Sent from my Samsung Galaxy smartphone.

ch...@chrismaness.com

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Apr 27, 2020, 6:04:19 PM4/27/20
to weewx...@googlegroups.com, jpronans, John Kline, gjr80, Dave Webb KB1PVH
On 4/27/20 11:05 AM, jpronans wrote:

> I reported it to one of the Sysops, but I understand remote access is
> problematic in the current environment.
>
> Regards,
> John
> EI7IG
>
I also reported this frustrating behavior to:

https://www.wxforum.net/index.php?topic=39321.new#new

Now I can work on improving my WX data quality.  Might have to ask the
local FD if I can mount a mast and an impeller at the local fire
department.  No good spot at my house, but maybe I can remedy that since
I am stuck home with this COVID lock down.  I don't think my wife would
be cool with a 40' mast, but hopefully I can get her to let me post it
up because of the emcomm aspect of having a radio tower.

Thanks for you help,

Chris KQ6UP

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