# LOGLVL > [HTML Version](loglvl.htm) LOGLVL_ _specifies the degree of detail to be written to the log file per the following table. It is ignored if LOGFILE_ _is blank or not present, and it defaults to 1 (Errors only) if LOGLVL_ _is not specified. The options are perhaps not completely self-explanatory, but the best way to understand them is just to experiment with a few sample messages and different settings. Typically you would just leave this set to 1 and check it periodically for error messages. Note that in the debug modes (4 and 5) the log file provides a rather graphic tutorial on how the SMTP protocol works, since it documents both the commands sent to the server and the responses received. | **Value** | **Result** | |------|------| | 0 | Off | | 1 | Errors only | | 2 | Info summary (to, from, number of bytes) | | 3 | Full message (to, from header, body) | | 4 | Partial debug (most commands and responses) | | 5 | Full debug (everything) | **History** 2023 June, A-Shell 6.5.1732, EMAILX.SBX(145): Add the Subject line (if present in the header) to the LOGLVL 4 output.