The LOGMARK target will log packet and connection marks to syslog.
.TP
\fB\-\-log\-level\fR \fIlevel\fR
A logging level between 0 and 8 (inclusive).
.TP
\fB\-\-log\-prefix\fR \fIstring\fR
Prefix log messages with the specified prefix; up to 29 bytes long, and useful
for distinguishing messages in the logs.