11. Troubleshooting

The following log file may be used to check Faxserver functionality: /var/log/ngcp/faxserver.log

11.1. Session ID (SID)

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


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

11.2. Fax Storage Location

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.