Snort Version 2.6.0by Martin Roesch and The Snort Team (http://www.snort.org/team.html)Distribution Site:http://www.snort.org******************************************************************************COPYRIGHTCopyright (C)2001-2006 Sourcefire Inc.Copyright (C)1998-2001 Martin RoeschThis program is free software; you can redistribute it and/or modifyit under the terms of the GNU General Public License as published bythe Free Software Foundation; either version 2 of the License, or(at your option) any later version.This program is distributed in the hope that it will be useful,but WITHOUT ANY WARRANTY; without even the implied warranty ofMERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See theGNU General Public License for more details.You should have received a copy of the GNU General Public Licensealong with this program; if not, write to the Free SoftwareFoundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.Some of this code has been taken from tcpdump, which was developedby the Network Research Group at Lawrence Berkeley National Lab,and is copyrighted by the University of California Regents.******************************************************************************DESCRIPTIONSnort is an open source network intrusion detection and prevention system.  Itis capable of performing real-time traffic analysis, alerting, blocking and packet logging on IP networks.  It utilizes a combination of protocol analysis and pattern matchingin order to detect a anomalies, misuse and attacks.  Snort uses a flexible rules language to describe activity that can be consideredmalicious or anomalous as well as an analysis engine that incorporates a modular plugin architecture.  Snort is capable of detecting and responding inreal-time, sending alerts, performing session sniping, logging packets, ordropping sessions/packets when deployed in-line.Snort has three primary functional modes.  It can be used as a packet sniffer like tcpdump(1), a packet logger (useful for network trafficdebugging, etc), or as a full blown network intrusion detection and preventionsystem.Please read the snort_manual.pdf file that should be included with this distribution for full documentation on the program as well as a guide to getting started.******************************************************************************[*][USAGE]Command line: 	snort -[options] <filters>Options:    -A <alert>  Set <alert> mode to full, fast or none.  Full mode            does normal "classic Snort"-style alerts to the alert            file.  Fast mode just writes the timestamp, message,             IP's, and ports to the file.  None turns off alerting.            There is experimental support for UnixSock alerts             that allow alerting to a separate process.  Use the             "unsock" argument to activate this feature.  There's also            the "cmg" option that prints out the full packet dump            with the alert information.  The "console" option prints            "fast" mode alerts to stdout, great for testing new rules            and debugging preprocessor anomaly detectors.    -b	    Log packets in tcpdump format.  All packets are logged            in their native binary state to a tcpdump formatted             log file called "snort.log".  This option results in            much faster operation of the program since it doesn't            have to spend time in the packet binary->text            converters.  Snort can keep up pretty well with 100Mbps            networks in "-b" mode.    -B <mask> Obfuscate IP addresses in alerts and packet dumps using             the provided CIDR mask as a substitution for the destination            IP addresses in events.    -c <cf>	Use configuration file <cf>.  This is puts Snort into IDS mode            and it reads the runtime configuration from <cf>.    -C      Dump the ASCII characters in packet payloads only, no            hex dump.    -d      Dump the application layer data.    -D      Run Snort in daemon mode.  Alerts are sent to            /var/log/snort/alert unless otherwise specified.    -e      Display/log the layer 2 packet header data.    -E      *WIN32 ONLY* Log alerts to the Windows Event Log.    -f      Activate PCAP line buffering.    -F <bpf> Read BPF filters from file <bpf>.  Handy for those of            you running Snort as a SHADOW replacement or with a            love of super complex BPF filters.    -g <gname> Run Snort as group ID <gname> after initialization.             This switch allows Snort to drop root privileges after            it's initialization phase has completed as a security            measure.    -G <id> Set a base event_id value for event generation, useful for            unified logging and alerting primarily.    -h <hn>	Set the "home network" to <hn>, which is a class C IP             address something like 192.168.1.0 or whatever.  If you            use this switch, traffic coming from external networks            will be formatted with the directional arrow of the             packet dump pointing right for incoming external             traffic, and left for outgoing internal traffic.  Kind            of silly, but it looks nice.    -i <if> Sniff on network interface <if>.      -I      Add the interface name to alert printouts (first interface only)    -J <port> When running in in-line mode on a system with divert sockets            this switch will select which <port> to read packets from.    -k <checksum mode>            Set <checksum mode> to all, noip, notcp, noudp, noicmp, or none.            Setting this switch modifies the checksum verification subsystem of            Snort to tune for maximum performance.  For example, in many            situations Snort is behind a router or firewall that doesn't allow            packets with bad checksums to pass, in which case it wouldn't make            sense to have Snort re-verify checksums that have already been             checked.  Turning off specific checksum verification subsystems can            improve performance by reducing the amount of time required to             inspect a packet.    -K <logging mode>            Set the packet output mode for logging.  There are three modes            available, pcap, ascii and none.  Pcap mode is the default, if            you don't specify a logging mode pcap is used now.  Pcap format            is the same as the -b switch, tcpdump format.  Ascii format is            the old default, it logs in the text-based "directories and files"<             format.  Be careful using ascii mode on uncontrolled networks, it            can exhaust your filesystem's inodes.  None mode turns off packet            logging.    -l <ld> Log packets to directory <ld>.  Sets up a hierarchical            directory structure with the log directory as the base            starting directory, and the IP address of the remote            peer generating traffic as the directory which packets            packets from that address are stored in.  If you do not             use the -l switch, the default logging directory is             /var/log/snort.              -L <fn> Set the binary output file's filename to <fn>.                -M      Log messages to syslog when running in non-daemon mode.            Has no impact on logging of alerts.    -m <mask> Set the umask for all of Snort's output files to the indicated             mask.    -n <cnt> Exit after processing <cnt> packets.    -N      Turn off logging.  Alerts still function normally.    -o      Change the order in which the rules are applied to             packets.  Instead of being applied in the standard            Alert->Pass->Log order, this will apply them in             Pass->Alert->Log order, allowing people to avoid having            to make huge BPF command line arguments to filter their            alert rules.      -O      Obfuscate the IP addresses when in ASCII packet dump            mode.  This switch changes the IP addresses that get            printed to the screen/log file to "xxx.xxx.xxx.xxx".            If the homenet address switch is set (-h), only             addresses on the homenet will be obfuscated while non-            homenet IP's will be left visible.  Perfect for posting            to your favorite security mailing list!    -p		Turn off promiscuous mode sniffing.  Useful for places            where that can screw up your host severely.    -P <snaplen> Set the snaplen of Snort to <snaplen>.  This filters how much             of each packet gets into Snort, the default is the MTU for the             interface that Snort is currently listening on.    -q	    Quiet. Don't show banner and status report.			    -Q      When running in-line, read packets from iptables/IPQ (on Linux).    -r <tf>	Read packets from the pcap formatted file <tf>.  This will cause             Snort to read and process the file fed to it as if the file was the            network.  This is essentially the same as tcpdump's readback mode.    -R <name> Add a custom sufffix to the snort pidfile.    -s      Log alert messages to the syslog.  On Linux boxen, they	        will appear in /var/log/secure, /var/log/messages on            many other platforms.  You can change the logging facility             by using the syslog output plugin, at which point the -s            switch should not be used (command line alert/log switches            override any config file output variables).    	-S <n=v> Set variable name "n" to value "v".  This is useful for            setting the value of a defined variable name in a Snort            rules file to a command line specified value.  For            instance, if you define a HOME_NET variable name inside            of a Snort rules file, you can set this value from            it's predefined value at the command line.    -t <chroot> Changes Snort's root directory to <chroot> after             initialization.  Please note that all log/alert filenames            are relevant to chroot directory, if chroot is used.    -T      Snort will start up in self-test mode, checking all the supplied            command line switches and rules files that are handed to it and            indicating that everything is ready to proceed.  This is a good            switch to use if daemon mode is going to be used, it verifies that            the Snort configuration that is about to be used is valid and             won't fail at run time.    -u <uname> Change the UID Snort runs under to <uname> after             initialization.    -U      Turn on UTC timestamps.                -v		Be verbose.  Prints packets out to the console.  There            is one big problem with verbose mode: it's still kind            of slow.  If you are doing IDS work with Snort, don't            use the -v switch, you WILL drop packets (not many, but            some).    -V      Show the version number and exit.    -w      If running on a 802.11 network, show management frames.    -W      *WIN32 ONLY* Enumerate the network interfaces available.    -X      Dump the raw packet data starting at the link layer.    -y      Turn on the year field in packet timestamps.    -Z <path> Set the perfmon path/filename to <path>.    -?      Show the usage summary and exit.Longname options and their corresponding single char version    --logid <0xid>                 Same as -G    --perfmon-file <file>          Same as -Z    --pid-path <path>              Specify the path for the Snort PID file    --snaplen <snap>               Same as -P    --help                         Same as -?    --dynamic-engine-lib <file>            Load a dynamic detection engine specified by <file>.    --dynamic-detection-lib <file>            Load a dynamic rules library specified by <file>.    --dynamic-detection-lib-dir <path>            Load all dynamic rules libraries from directory specified            by <path>.    --dump-dynamic-rules <path>            Creates stub rule files of all loaded rules libraries            specified by <path>.  Required to be done prior to            runing snort to detect those rules.  Generated rules stub            files must be 'include'ed in snort.conf.    --dynamic-preprocessor-lib <file>            Load a dynamic preprocessor library specified by <file>.    --dynamic-preprocessor-lib-dir <path>            Load all dynamic preprocessor libraries from directory            specified by <path>.    --dump-dynamic-preproc-genmsg <path>            Creates gen-msg.map files of all loaded preprocessor            libraries in <path>.    --alert-before-pass            Process alert, drop, sdrop, or reject before pass.            Default is pass before alert, drop, etc.    --treat-drop-as-alert            Converts drop, sdrop, and reject rules into alert rules            during startup.    --process-all-events            Process all triggered events in group order, per Rule Ordering            configuration.  Default stops after first group.    --pid-path <path>            Specify the path for Snort's PID file.    --create-pidfile            Create PID file, even when not in Daemon mode.[*][FILTERS]:     The "filters" are standard BPF style filters as seen in tcpdump.  Lookat the man page for snort for docs on how to use it properly.  In general,you can give it a host, net or protocol to filter on and some logical statementsto tie it together and get the specific traffic you're interested in.  For example:[zeus ~]# ./snort -h 192.168.1.0/24 -d -v host 192.168.1.1records the traffic to and from host 192.168.1.1.[zeus ~]# ./snort -h 192.168.1.0/24 -d -v net 192.168.1 and not host 192.168.1.1records all traffic on the 192.168.1.0/24 class C subnet, but not traffic to/from 192.168.1.1.  Notice that the command line data specified after the"-h" switch is formated differently from the BPF commands provided at the end of the command line.  Sorry for the confusion, but I like the CIDR notation andI'm not rewriting libpcap to make it consistent!  Anyway, you get the picture.Mail me if you have trouble with it.You can use the -F switch to read your BPF filters in from a file.  [*][RULES]:      -------------------------------------------------------------------------NOTE: The "official" rules document these days is available at:http://www.snort.org/docs/writing_rules/and is also usually distributed as snort_manual.pdf in the distro.  Ifyou don't have this file in your distribution of Snort, you can get it fromwww.snort.org.-------------------------------------------------------------------------Please read the USAGE file or the snort_manual.pdf for more info!******************************************************************************/* $Id: README,v 1.30 2006/02/23 16:32:29 ssturges Exp $ */