Android Question Why does B4A send broadcast message every 1 sec on port 58912? [Solved]

[Boon]

I noticed that Led light at my switch is blinking after open B4A, so I use Wireshark to check it out and found that if B4A is running, there is broadcast messages sending from my Windows machine on port UDP 58912 every 1 second. Is it normal to be like this? What is its purpose? I hope it is not a bug of B4A because it consumes network bandwidth.
Thanks.

 

[JohnC]

It could be that B4A is trying to discover any devices running B4Bridge or allow devices running B4Bridge to find B4A so they can establish a link easier then having to enter IP addresses all the time.

B4Bridge is an app that you can download from the Play Store that allows B4A to link to a local device over WiFi instead of using a USB connection.

 

[BillMeyer]

Are you using B4A Bridge ?

How does your PC communicate with this ?

This might be the solution to your question.

 

[JohnC]

B4A doesn't know if there are any B4ABridge devices out there until it does a ping (which B4Abridge devices would then respond to), so it will probably keep doing these pings to keep "looking" for B4Abridge devices on a continuous basis (even if you are currently not using B4ABridge) so it can quickly "find" any new B4Abridge devices if/when you eventually hook one up.

As you noticed its a UDP packet not a TCP, so it's probably a very small packet and is probably limited to the local network (doesn't go out on the internet). So, it should be nothing to worry about.

 

[Vader]

Routers block UDP. Yes, local subnet only.

 

[Boon]

Thanks for all the replies. It could be B4A broadcast messages to let B4ABridge devices know that I'm here(at this IP address) like you guys said. Anyway, if they can make B4A send it every 5 seconds, it would be better. Imagine if you have 10 developers sitting in the same network, there would be a lot of broadcast messages in each second.

 

[Vader]

It's very standard to broadcast UDP on a per second basis. As it's UDP and thus connectionless its a very light protocol and can be ignored. This means that something can ignore them until the time is right, and then wait a maximum of 1 second. I would ignore it. Of course they are also not stored or rebroadcast so at most there is only 1 message current.

 

[Erel]

It is indeed related to the auto discovery of B4A-Bridge clients.

The message size is a single byte and it is sent over the local network. You can change the interval by modifying UdpServerInterval in the ini file.
The bandwidth usage is negligible.