FlightAware Discussions

Lots of Port 123

The more you get in to this the more you wonder.

I have a PiAware system feeding also FR24 and ADSBx, out of curiosity I was checking various connections through my router admin page and noticed quite a few going out to port 123.

Appreciate this is used for NTP time servers but when I did a whois on the destination IP addresses I don’t get any info suggesting it is a time server.

The locations shown for the IP addresses are Russia, Morocco, Brasil, Canada, NZ and China, guessing that due to the varied locations it might be something to do with the mlat syncing although I thought that was done with other mlat devices reasonably close by.



MLAT is all done on the FA servers(unless you setup your own system).
There is no need to even have NTP running on a device.

If you need NTP then you can setup your own server for about $US50. It doesn’t even require and Internet connection.
I have the new and older model. The new one does Galileo as well as GLONASS and GPS.

XGPS once I got Galileo to work.
Square are SBAS (WAAS in this case), Circle is GPS, Diamond ins Glonass and Triangle is Galileo. This is using a decent antenna inside my attic.


The PiAware image uses the default Raspbian NTP configuration, which uses pool.ntp.org, which points to a large pool of volunteer NTP servers spread around the world; so this is normal.

I believe the FR24 feeder does its own NTP, so that may be contributing to connections.

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Not quite, that pool will try and chose local servers.
So far off places should be the exception.

Isn’t the Raspbian default configuration using systemd-timesyncd?
That doesn’t do many ntp requests at all, not meant to be as precise as the normal ntp installation.

It does stupid NTP, pinging all the following pools and then using one of them that answers:


It does that every 10 minutes without any regard for pool guidelines whatsoever.

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I mean default-if-you-install-ntpd. I need to doublecheck the current image does the right thing, but the intent is to have ntpd there.

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Then you might want to recommend installing the ntp package when installing on a standalone Raspbian.
(Or just include it into the dependencies)
But for systemd-timesyncd checks time every couple of hours, that should be good enough for most purposes.

Also curious about the up to 1 second flush time for TCP packets in dump1090-fa.
Not talking MLAT here obviously but normal ADS-B packets.

It’s mostly so we can actually interrogate ntpd to see if the system clock is reasonable or not. Sub-second accuracy doesn’t really matter but knowing the system clock is at least approximately correct is useful.

Nothing much in the piaware image is sensitive to short timescales like that.

Why not just set it to 0.1 seconds, it’s not like 10 packets per second is any load on the system.
With a little bit of traffic you get to that number of packets anyway.

Oh well you’re probably right and no one cares.
Most of the time the 1000 Byte limitation is gonna ensure timely delivery anyway.


Except for something like a station in the middle of Indian Ocean that sees 4 planes a day.


Eight so far today but who is counting. :joy:



It’s mostly an arbitrary value. There’s no compelling reason that it should be 1 second, but there’s also no compelling reason to change it to 0.1s and retest everything.

Is really that station name URSS in Cyrillic script? :smiley:


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At least it is the icao code of the nearest airport, Cocos-Keeling-Island International


Aren’t you happy that you don’t care about FA rankings?:rofl:

Are you a hamradio operator? That’s a highly sought after ‘entity’ in hamradio DXing ‘circles’.


I can’t imagine what prompted you to look up that translation nor what i can do with that information now that i have it. I slept so much better last night knowing it :sweat_smile:

I looked at the rankings a while ago and decided that unless you lived in the most densely flown parts of the world and probably had multiple receivers aggregating data it was irrelevant.

I do it for my own satisfactionand compare my figures to the nearby other stations to see if i am doing as well as i can.

To misquote the great Mel Brookes, “Rankings, we don’t need no stinking rankings”

Yes. I haven held licences in three countries and still have in two.

I don’t live on Cocos nor have i visited. It was just opportunistic to be able to have a Flightaware receiver there.

I have lived in a DX hotspot (VS6) before internet and cheap international calls. I used 20M to talk to my then girlfriend and obnoxious multi kilowatt paper chasers kept coming over the top of her. I lost interest in sendingQSL cards.

Christmas island has a radio club.



My kind of a guy. No silly competitions.:grinning:

They are still out there, ready to ruin other people’s conversations.

I’ve been a ham for 39 years, but I have very little respect for hams as a ‘class’. Still a great hobby though, with some great people.


@SweetPea11 I grew up with the shadow of USSR/URSS over my country and, as kids in school, we were strongly encouraged to know the spelling in their alphabet (even if we didn’t use it).
So that indicative just jumped in my face and I thought that was funny to point it out.