The system log is supported by the syslogd(1M) program. All messages from sendmail(1M) are logged under the LOG_MAIL facility.
Each line in the system log consists of a timestamp, the name of the
machine that generated it (for logging from several machines over the
local area network), the word sendmail:
, and a message.
Most messages are a sequence of name=value pairs.
The two most common lines are logged when a message is processed. The first logs the receipt of a message; there will be exactly one of these per message. Some fields may be omitted if they do not contain interesting information. The fields are:
from
size
class
pri
nrcpts
msgid
proto
relay
to
ctladdr
delay
xdelay
mailer
relay
stat
If you have syslogd(1M) or an equivalent installed, you will be able to do logging. There is a large amount of information that can be logged. The log is arranged as a succession of levels. At the lowest level only extremely strange situations are logged. At the highest level, even the most mundane and uninteresting events are recorded for posterity. As a convention, log levels under ten are considered generally useful; log levels above 64 are reserved for debugging purposes. Levels from 11-64 are reserved for verbose information that some sites might want.
A complete description of the log levels is given in ``Log level''.