FS responds 488 to t38 reinvite for some bridge syntax

FreeSWITCH
1

Hello,

I noted that FS handles t38 reinvites differently some cases below:

  1. session:execute(“bridge”, “user/”… user …“@${domain_name}”)
    Grandsteam ata sends reinvite with t38 and it work perfectly.
  2. But if I use this syntax
    session:execute(“bridge”, “${sofia_contact(”… user …“@${domain_name})}”)
    FS responds with 488 Not Acceptable to ABSOLUTELY same reinvite from Grandstem. Again. There is no difference in reinvite. Also it is the same lua script. I just change two strings above.

In lua i also have
session:execute(“export”, “38_passthru=true”)
session:execute(“export”, “fax_enable_t38=true”)

FreeSWITCH Version 1.10.11-release-25-f24064f7c9~64bit (-release-25-f24064f7c9 64bit)
Debian 12

Please advice.

2

Well. I used syntax like this
session:execute(“bridge”, “${sofia_contact(”… jtuser …“@${domain_name})}^”… DID …“”)
to change TO sip header.
But like i mentioned this syntax has bug with t38 reinvites.
For now I have made workaround and use kamailio to change TO header.
At FS i just use
session:execute(“bridge”, “user/”… user …“@${domain_name}”)
and have not problmes with t38 reinvites.