.TP
[\fB!\fP] \fB\-\-mac\-source\fP \fIaddress\fP
Match source MAC address.  It must be of the form XX:XX:XX:XX:XX:XX.
Note that this only makes sense for packets coming from an Ethernet device
and entering the
.BR PREROUTING ,
.B FORWARD
or
.B INPUT
chains.
