Asterisk Log Files
Log file location
Asterisk log files are located in the directory /var/log/asterisk. There are a variety of different types of log files, generally one file per day going back a certain number of days.
The "full" log is the most detailed, describing each call in great detail.
Working with log files
The FreePBX web GUI can be used to view these log files – see Asterisk Logfiles
For more detailed log file analysis, the grep command line tool is helpful
Another tool helpful in call analysis are call display reports, especially clicking on a call's System Unique ID number to see the Call Event Log breakdown for that particular call – see CDR Reports Module
Configure log file history retention
Other log files to note
The system log file in /var/log/messages has TFTP server log information, which can be helpful troubleshooting phone configuration – see View TFTP requests from phones
The log file /var/spool/mail/asterisk logs e-mail sending activity