Ubuntu Manpage: portsentry - detect portscan activity

NAME

       portsentry - detect portscan activity

SYNOPSIS

       portsentry [ -tcp | -stcp | -atcp ]
       portsentry [ -udp | -sudp | -audp ]

DESCRIPTION

       This  manual  page documents briefly the portsentry command.  This manual page was written
       for the Debian GNU/Linux distribution because the original program does not have a  manual
       page.

       portsentry  is  a  program  that  tries to detect portscans on network interfaces with the
       ability to detect stealth scans. On alarm portsentry can block the  scanning  machine  via
       hosts.deny   (see   hosts_access(5),   firewall  rule  (see  ipfwadm(8),  ipchains(8)  and
       iptables(8)) or dropped route (see route(8)).

OPTIONS

       For details on the various modes see /usr/share/doc/portsentry/README.install

       -tcp   tcp portscan detection on ports  specified  under  TCP_PORTS  in  the  config  file
              /etc/portsentry/portsentry.conf.

       -stcp  As above but additionally detect stealth scans.

       -atcp  Advanced  tcp  or  inverse  mode.  Portsentry  binds  to  all  unused  ports  below
              ADVANCED_PORTS_TCP given in the config file /etc/portsentry/portsentry.conf.

       -udp   udp portscan detection on ports  specified  under  UDP_PORTS  in  the  config  file
              /etc/portsentry/portsentry.conf.

       -sudp  As above but additionally detect "stealth" scans.

       -audp  Advanced  udp  or  inverse  mode.  Portsentry  binds  to  all  unused  ports  below
              ADVANCED_PORTS_UDP given in the config file /etc/portsentry/portsentry.conf.

CONFIGURATION FILES

portsentry keeps all its configuration files in /etc/portsentry. portsentry.conf is
portsentry's main configuration file. See portsentry.conf(5) for details.

The file portsentry.ignore contains a list of all hosts that are ignored, if they connect
to a tripwired port. It should contain at least the localhost(127.0.0.1), 0.0.0.0 and the
IP addresses of all local interfaces. You can ignore whole subnets by using a notation <IP
Address>/<Netmask Bits>. It is *not* recommend putting in every machine IP on your
network. It may be important for you to see who is connecting to you, even if it is a
"friendly" machine. This can help you detect internal host compromises faster.

If you use the /etc/init.d/portsentry script to start the daemon, portsentry.ignore is
rebuild on each start of the daemon using portsentry.ignore.static and all the IP
addresses found on the machine via ifconfig.

/etc/default/portsentry specifies in which protocol modes portsentry should be startet
from /etc/init.d/portsentry There are currently two options:

TCP_MODE=
either tcp, stcp or atcp (see OPTIONS above).

UDP_MODE=
either udp, sudp or audp (see OPTIONS above).

The options above correspond to portsentry's commandline arguments. For example
TCP_MODE="atcp" has the same effect as to start portsentry using portsentry -atcp. Only
one mode per protocol can be started at a time (i.e. one tcp and one udp mode).

FILES

       /etc/portsentry/portsentry.conf main configuration file

       /etc/portsentry/portsentry.ignore
              IP addresses to ignore

       /etc/portsentry/portsentry.ignore.static
              static IP addresses to ignore

       /etc/default/portsentry
              startup options

       /etc/init.d/portsentry
              script responsible for starting and stopping the daemon

       /var/lib/portsentry/portsentry.blocked.*
              blocked hosts(cleared upon reload)

       /var/lib/portsentry/portsentry.history
              history file

AUTHOR

       portsentry was written by Craig H. Howland <crowland@users.sf.net>.

       This manual page was stitched together by Guido Guenther <agx@debian.org>, for the  Debian
       GNU/Linux system (but may be used by others). Some parts are just a cut and paste from the
       original documentation.

                                                                                    PORTSENTRY(8)