[asterisk-users] t.38 interop with metaswitch

[Jeremy Kister]

I'm trying to receive a t.38 fax from a Metaswitch 7.3.  I have full 
control over the metaswitch, but it is in production.

I have the Metaswitch hooked to Asterisk 1.8.7.0 (middleman named s3). 
Then I have the target Asterisk 1.8.7.0 with res_fax_digum 1.8.4_1.3.0 
(named pbx1) registered to s3.

attempts to receive fax over t.38 always error in res_fax with "fax 
session timed-out"

i have debug output at:
  http://jeremy.kister.net/tmp/t38/pbx1.txt
  http://jeremy.kister.net/tmp/t38/s3.txt

is the UDPTL debug on pbx1.txt (near line 474) interesting in that 
LOG_TAG(s) is evaluated to 'SIP/' ?

I don't think my (sip|udptl|extensions).conf are interesting, but i'd be 
happy to post them.  the only interesting tidbit is that when i changed 
't38pt_udptl=yes' to 'yes,none' or 'yes,redundancy' the fax would fail 
with 't38 negotiation failed".

fyi, g711/rtp audio detected faxes are working fine.

anyone have suggestions on what i can try next?

-- 

Jeremy Kister
http://jeremy.kister.net./