The following log file may be used to check Faxserver functionality: /var/log/ngcp/faxserver.log
Faxserver stores basic information about each processed fax in a session file. The most important element within this set of data is the Session ID (SID) that uniquely identifies a fax throughout its lifetime.
Session ID is a long hexadecimal string (a kind of UUID) that can be read from the above mentioned Faxserver logfile, and which itself is used also as the filename in files that belong to a specific sent / received fax. An example:
root@sp1:~# cat /ngcp-data/spool/faxserver/failed/1e480167-5de6-4cc2-948b-de58d1a0bb8c.err created: 2016-09-06 04:41:32 caller: 111111111 callee: 222222222 file: 1e480167-5de6-4cc2-948b-de58d1a0bb8c.tif sid: 1e480167-5de6-4cc2-948b-de58d1a0bb8c dir: out attempts: 0 fail_attempts: 3 fail_retry_secs: 60 quality: normal status: FAILED error: Internal error modified: 2016-09-06 17:41:30 root@sp1:~#
The data element sid is the session ID. Other important elements are:
caller and callee: these are probably searched for when trying to figure
out what happened to a specific fax transmission, if you don’t know the SID
dir: direction of fax transmission: in’coming or 'out’going or 'mtf
for mail-to-fax
status: shows success or failure
error: the error cause in case of failed faxes
Faxserver stores all of its processed faxes at the path: /ngcp-data/spool/faxserver/…
Within that directory the most relevant subdirectories are failed and completed
that store the SID file and the fax itself in TIFF format of those faxes that failed
or were successful, respectively.