ZeroTAK and ICU

Hi all,

Noob question regarding the ICU app.

I made a network for a ZeroTAK configuration and I encounter a weird fail.

Tests have been made using wifi and cellular data from both phones, with the same results.

2 smartphones both running ATAK and Zerotier-One. Text messages and positions work perfectly. When testing live video broadcast with ICU:
Phone 1 can broadcast (, see the marker or play the live stream from phone 2.
Phone 2 can broadcast (, see the marker but cannot play the live stream from phone 1. States connexion failed.

ICU settings are:

Destination type: LAN
Delivery method: UDP
Use last octet: unchecked
Broadcast adress:
Broadcast TTL: 1

What could cause the failure to connect to the stream?

Any help would be much appreciated


Thanks for writing.
I don’t know much about the ATAK app. One guess is the zerotier-one app isn’t working too great at the moment. It might be worth it to try an older version, if you have an easy way to load it. The apk is here

New releases of the android app coming soon.

Thanks for answering,

I’m using ZT because of recent problems with the update, it seems to work great for everything except this particular problem.

We are making as many tests as possible so we can get clues to what’s wrong. I hope we will find why so we could document it for other users.

Curious if you got this to work, as I’ve also been thinking about ZT as a solution for ATAK, in particular because it gets around the lack of broadcast/multicast on LTE.

The one thing that looks a bit suspect to me in your setup is the TTL of 1. Have you tried it with a higher TTL? Does anything change with a TTL of 3 or 4? In a test environment that shouldn’t crush the network and it would at least rule out one source of problems.

My next step would be to Wireshark the thing and see what’s going on with the actual packet flow.

I will try with a higher TTL, if I ever find a solution I’ll give feedback

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