.TH l7-filter  "1" "January 2007" "l7-filter v0.3" "User's Manual".SH NAMEl7-filter \- classifies packets by their application layer data\fB.SH SYNOPSIS.B l7-filter -f \fIconfiguration_file\fR [\fIoptions\fR].SH DESCRIPTION.PPl7-filter reads packets that are queued by Netfilter/iptables and marks them based on what application layer protocol they appear to be..SH OPTIONS.TP.B -f \fIconfiguration_file\fRMandatory option.  This file consists of pairs of protocol names and mark numbers..TP.B -q \fIqueue_number\fRWhat queue to read packets from.  Default is 0..TP.B -b \fIbytes\fRMatch on up to this many bytes of application layer data.  The default is12000..TP.B -n \fIpackets\fRExamine up to this many packets in each connection.  If no match has beenmade after this, l7-filter gives up.  The number of packets counts all packets,including the TCP handshake and ACK packets (XXX but not any UDP packets thatl7-filter didn't manage to get the conntrack for in time XXX)..TP.B -p \fIpath\fRLook for patterns in \fIpath\fR instead of the default /etc/l7-protocols.The path and its subdirectories are searched, non-recursively (subsubdirectories are not searched)..TP.B -m \fImask\fRUse only the bits of the packet mark specified by the given \fImask\fR. By default, l7-filter uses the whole 32 bit mark, so this is useful if you use other classifiers that set marks. For instance, if you give the mask 0xff000000, l7-filter will only use the first 8 bits of the mark and will completely ignore the rest of it.  In this case, the mark numbers given in the configuration file are mapped onto the mask automatically.  So if the configuration file says 2 and you'vegiven the mask 0x00ff0000, l7-filter will actually use 0x00020000.The mask must be contiguous (not, for instance, 0x00000f0f) and it must be at least 2 bits long.  The number of protocols that l7-filter can handle is 2^(mask length)-3 since it uses the value 0 to detect when a packet has not been examined yet, 1 to mark packets in connections which are unmatched but still being examined, and 2 to mark packets which it has given up trying to identify..TP.B -cl7-filter expects its portion of the packet mark (see -m above) to beunmodified by other classifiers.  Normally, if it gets a packet whose markhas already been modified (that is, is non-zero) in this region, itwill send the packet on with the same mark without trying to classify itand print an error message.  This option causes l7-filter instead to clobber the existing mark and classify as if it hadn't been there..TP.B -sBe silent (don't print anything) except in the case of warnings or errors..TP.B -vBe verbose.  Gives more information about what l7-filter is doing.  Multiple -voptions increase the verbosity, up to a maximum of 4..TP.B -dAllow inadvisable configurations.  You must give this option before the optionwhich is inadvisable..SH UPGRADESThe latest version is always at http://sf.net/projects/l7-filter.SH "SEE ALSO".BR iptables (1).SH COPYRIGHT.PPCopyright \(co 2006-2007 Ethan Sommer <sommereAusers.sf.net> and Matthew Strait <quadongAusers.sf.net>.  This is free software.  You may redistribute copies of it under the terms of the GNU General Public License <http://www.gnu.org/licenses/gpl.html>. There is NO WARRANTY, to the extent permitted by law.