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I've been using Zoiper (over UDP) for a while now but due to a few (timing) problems, I've switched to TCP yesterday. It was working fine until early today when my zoiper went into a state that it was unable to register (register timeout 408).

Situation is as follows:

- Green zoiper tick is missing from notificationsbar in android.
- Zoiper shows "register timeout 408", no incoming calls possible. Asterisk "sip peers" command shows the extension as unreachable.


  • I start a tcpdump which suggests that Zoiper sends a "tcp syn" to port 5060.
  • The server responds with a "tcp sync ack" and zoiper answers with a "tcp ack".
  • In the meanwhile, asterisk expects a REGISTER to occur, but after 30 seconds it still hasn't received a proper response and sends a "tcp fin" to zoiper.

It seems that in some situations, Zoiper keeps using the same port (in my debuglog port 56630) when sending the REGISTER to the server.

Here is a link to a zip containing some zoiper debuglogs as well as a tcpdump:

In the end, the problem is solved if I exit Zoiper completely.

in Android by (160 points)

1 Answer

+1 vote
Best answer

Which is the exact version of Android that you are running on your devices?
Try using TLS transport or have your  server use port different than 5060.

by (23.9k points)
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Thanks for your response.

The device is a Moto G (XT1032) running on Android 5.1.

I haven't configured TLS yet, but would that differ much with TCP except for the encryption?

Did you try using different ports?

I have configured TLS and Asterisk debug shows it is using port 5061 instead of 5060. So far, the problem hasn't occured again (only been testing for one day).

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