Pjsip prack

FreePBX Providers
1

Hi All,

Since we migrated our trunks towards PJSIP, we notice that FPBX is generating PRACK messages towards our ITSP.
2 questions:

  • Is there any way to disable that behavior? (in the trunk configuration?)
  • Is this really needed? :slight_smile:

Thanks for your help!

2

Usually, PRACK is a good thing. Otherwise, a single lost packet could cause the caller to not hear ringback tone or an early media announcement. What trouble is it causing?

3

If the provider doesn’t want PRACK, they shouldn’t request it by claiming 100rel support.

There is a 100rel option, but I’m not entirely sure which direction(s) it controls, and don’t know if there is GUI support. In any case, I can’t think why you would want to disable it.

4

Thanks for your replies @Stewart1 & @david55.

Some outbound calls are being cut by our ITSP (by malformed PRACK messages), and their first thought would be to disable them.

If I understand correctly, these were not present on our CHAN_SIP trunks… so I would assume we don’t need them now either :).

5

I’m pretty sure setting 100rel=no will disable it (but may have to be done in a customisation file). However, I’d be very surprised if something that caused it to be malformed had not been found by others, unless it is the result of misconfiguration, or a router is modifying it.

6

Thanks a lot @david55 ! As a workaround I added 100rel=no to the pjsip.endpoint_custom_post.conf file and PRACK messages are not present anymore.

7

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