portsentry and iptables

[Deedra Waters]

I've read  the documentation for portsentry, but am having a lot of
trouble getting it going. my main problems are with the portsentry.conf
fileI'm really confused as to how to get it going, and working correctly
with the iptables I have set up... if someone could help me with this I'd
appreciate it... I'm attaching the portsentry.conf file to this message...

Like I said, I've read the readme files and the portsentry.conf file
itself, but am still really confused as to how to set it up and what to
comment and uncomment in it.
and what to change.

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# PortSentry Configuration
#
# $Id: portsentry.conf,v 1.23 2001/06/26 15:20:56 crowland Exp crowland $
#
# IMPORTANT NOTE: You CAN NOT put spaces between your port arguments.
# 
# The default ports will catch a large number of common probes
#
# All entries must be in quotes.


#######################
# Port Configurations #
#######################
#
#
# Some example port configs for classic and basic Stealth modes
#
# I like to always keep some ports at the "low" end of the spectrum.
# This will detect a sequential port sweep really quickly and usually
# these ports are not in use (i.e. tcpmux port 1)
#
# ** X-Windows Users **: If you are running X on your box, you need to be sure
# you are not binding PortSentry to port 6000 (or port 2000 for OpenWindows users). 
# Doing so will prevent the X-client from starting properly. 
#
# These port bindings are *ignored* for Advanced Stealth Scan Detection Mode.
#

# Un-comment these if you are really anal:
#TCP_PORTS="1,7,9,11,15,70,79,80,109,110,111,119,138,139,143,512,513,514,515,540,635,1080,1524,2000,2001,4000,4001,5742,6000,6001,6667,12345,12346,20034,27665,30303,32771,32772,32773,32774,31337,40421,40425,49724,54320"
#UDP_PORTS="1,7,9,66,67,68,69,111,137,138,161,162,474,513,517,518,635,640,641,666,700,2049,31335,27444,34555,32770,32771,32772,32773,32774,31337,54321"
#
# Use these if you just want to be aware:
TCP_PORTS="1,11,15,79,111,119,143,540,635,1080,1524,2000,5742,6667,12345,12346,20034,27665,31337,32771,32772,32773,32774,40421,49724,54320"
UDP_PORTS="1,7,9,69,161,162,513,635,640,641,700,37444,34555,31335,32770,32771,32772,32773,32774,31337,54321"
#
# Use these for just bare-bones
#TCP_PORTS="1,11,15,110,111,143,540,635,1080,1524,2000,12345,12346,20034,32771,32772,32773,32774,49724,54320"
#UDP_PORTS="1,7,9,69,161,162,513,640,700,32770,32771,32772,32773,32774,31337,54321"

###########################################
# Advanced Stealth Scan Detection Options #
###########################################
#
# This is the number of ports you want PortSentry to monitor in Advanced mode.
# Any port *below* this number will be monitored. Right now it watches 
# everything below 1024. 
# 
# On many Linux systems you cannot bind above port 61000. This is because
# these ports are used as part of IP masquerading. I don't recommend you
# bind over this number of ports. Realistically: I DON'T RECOMMEND YOU MONITOR 
# OVER 1024 PORTS AS YOUR FALSE ALARM RATE WILL ALMOST CERTAINLY RISE. You've been
# warned! Don't write me if you have have a problem because I'll only tell
# you to RTFM and don't run above the first 1024 ports.
#
#
ADVANCED_PORTS_TCP="1024"
ADVANCED_PORTS_UDP="1024"
#
# This field tells PortSentry what ports (besides listening daemons) to
# ignore. This is helpful for services like ident that services such 
# as FTP, SMTP, and wrappers look for but you may not run (and probably 
# *shouldn't* IMHO). 
#
# By specifying ports here PortSentry will simply not respond to
# incoming requests, in effect PortSentry treats them as if they are
# actual bound daemons. The default ports are ones reported as 
# problematic false alarms and should probably be left alone for
# all but the most isolated systems/networks.
#
# Default TCP ident and NetBIOS service
ADVANCED_EXCLUDE_TCP="113,139"
# Default UDP route (RIP), NetBIOS, bootp broadcasts.
ADVANCED_EXCLUDE_UDP="520,138,137,67"


######################
# Configuration Files#
######################
#
# Hosts to ignore
IGNORE_FILE="/usr/local/psionic/portsentry/portsentry.ignore"
# Hosts that have been denied (running history)
HISTORY_FILE="/usr/local/psionic/portsentry/portsentry.history"
# Hosts that have been denied this session only (temporary until next restart)
BLOCKED_FILE="/usr/local/psionic/portsentry/portsentry.blocked"

##############################
# Misc. Configuration Options#
##############################
#
# DNS Name resolution - Setting this to "1" will turn on DNS lookups
# for attacking hosts. Setting it to "0" (or any other value) will shut
# it off.
RESOLVE_HOST = "1"

###################
# Response Options#
###################
# Options to dispose of attacker. Each is an action that will 
# be run if an attack is detected. If you don't want a particular
# option then comment it out and it will be skipped.
#
# The variable $TARGET$ will be substituted with the target attacking
# host when an attack is detected. The variable $PORT$ will be substituted
# with the port that was scanned. 
#
##################
# Ignore Options #
##################
# These options allow you to enable automatic response
# options for UDP/TCP. This is useful if you just want
# warnings for connections, but don't want to react for  
# a particular protocol (i.e. you want to block TCP, but
# not UDP). To prevent a possible Denial of service attack
# against UDP and stealth scan detection for TCP, you may 
# want to disable blocking, but leave the warning enabled. 
# I personally would wait for this to become a problem before
# doing though as most attackers really aren't doing this.
# The third option allows you to run just the external command
# in case of a scan to have a pager script or such execute
# but not drop the route. This may be useful for some admins
# who want to block TCP, but only want pager/e-mail warnings
# on UDP, etc.
#
# 
# 0 = Do not block UDP/TCP scans.
# 1 = Block UDP/TCP scans.
# 2 = Run external command only (KILL_RUN_CMD)

BLOCK_UDP="1"
BLOCK_TCP="1"

###################
# Dropping Routes:#
###################
# This command is used to drop the route or add the host into
# a local filter table. 
#
# The gateway (333.444.555.666) should ideally be a dead host on 
# the *local* subnet. On some hosts you can also point this at
# localhost (127.0.0.1) and get the same effect. NOTE THAT
# 333.444.555.66 WILL *NOT* WORK. YOU NEED TO CHANGE IT!!
#
# ALL KILL ROUTE OPTIONS ARE COMMENTED OUT INITIALLY. Make sure you
# uncomment the correct line for your OS. If you OS is not listed
# here and you have a route drop command that works then please
# mail it to me so I can include it. ONLY ONE KILL_ROUTE OPTION
# CAN BE USED AT A TIME SO DON'T UNCOMMENT MULTIPLE LINES.
#
# NOTE: The route commands are the least optimal way of blocking
# and do not provide complete protection against UDP attacks and
# will still generate alarms for both UDP and stealth scans. I
# always recommend you use a packet filter because they are made
# for this purpose.
#

# Generic 
#KILL_ROUTE="/sbin/route add $TARGET$ 333.444.555.666"

# Generic Linux 
#KILL_ROUTE="/sbin/route add -host $TARGET$ gw 333.444.555.666"

# Newer versions of Linux support the reject flag now. This 
# is cleaner than the above option.
#KILL_ROUTE="/sbin/route add -host $TARGET$ reject"

# Generic BSD (BSDI, OpenBSD, NetBSD, FreeBSD)
#KILL_ROUTE="/sbin/route add $TARGET$ 333.444.555.666"

# Generic Sun 
#KILL_ROUTE="/usr/sbin/route add $TARGET$ 333.444.555.666 1"

# NEXTSTEP
#KILL_ROUTE="/usr/etc/route add $TARGET$ 127.0.0.1 1"

# FreeBSD
#KILL_ROUTE="route add -net $TARGET$ -netmask 255.255.255.255 127.0.0.1 -blackhole"

# Digital UNIX 4.0D (OSF/1 / Compaq Tru64 UNIX)
#KILL_ROUTE="/sbin/route add -host -blackhole $TARGET$ 127.0.0.1"

# Generic HP-UX
#KILL_ROUTE="/usr/sbin/route add net $TARGET$ netmask 255.255.255.0 127.0.0.1"

##
# Using a packet filter is the PREFERRED. The below lines
# work well on many OS's. Remember, you can only uncomment *one*
# KILL_ROUTE option.
##

# ipfwadm support for Linux
#KILL_ROUTE="/sbin/ipfwadm -I -i deny -S $TARGET$ -o"
#
# ipfwadm support for Linux (no logging of denied packets)
#KILL_ROUTE="/sbin/ipfwadm -I -i deny -S $TARGET$"
#
# ipchain support for Linux
#KILL_ROUTE="/sbin/ipchains -I input -s $TARGET$ -j DENY -l"
#
# ipchain support for Linux (no logging of denied packets)
#KILL_ROUTE="/sbin/ipchains -I input -s $TARGET$ -j DENY"
#
# iptables support for Linux
#KILL_ROUTE="/usr/local/bin/iptables -I INPUT -s $TARGET$ -j DROP"
#
# For those of you running FreeBSD (and compatible) you can
# use their built in firewalling as well. 
#
#KILL_ROUTE="/sbin/ipfw add 1 deny all from $TARGET$:255.255.255.255 to any"
#
#
# For those running ipfilt (OpenBSD, etc.)
# NOTE THAT YOU NEED TO CHANGE external_interface TO A VALID INTERFACE!!
#
#KILL_ROUTE="/bin/echo 'block in log on external_interface from $TARGET$/32 to any' | /sbin/ipf -f -"


###############
# TCP Wrappers#
###############
# This text will be dropped into the hosts.deny file for wrappers
# to use. There are two formats for TCP wrappers:
#
# Format One: Old Style - The default when extended host processing
# options are not enabled.
#
KILL_HOSTS_DENY="ALL: $TARGET$"

# Format Two: New Style - The format used when extended option
# processing is enabled. You can drop in extended processing
# options, but be sure you escape all '%' symbols with a backslash
# to prevent problems writing out (i.e. \%c \%h )
#
#KILL_HOSTS_DENY="ALL: $TARGET$ : DENY"

###################
# External Command#
###################
# This is a command that is run when a host connects, it can be whatever
# you want it to be (pager, etc.). This command is executed before the 
# route is dropped or after depending on the KILL_RUN_CMD_FIRST option below
#
#
# I NEVER RECOMMEND YOU PUT IN RETALIATORY ACTIONS AGAINST THE HOST SCANNING 
# YOU!
#
# TCP/IP is an *unauthenticated protocol* and people can make scans appear out 
# of thin air. The only time it is reasonably safe (and I *never* think it is 
# reasonable) to run reverse probe scripts is when using the "classic" -tcp mode. 
# This mode requires a full connect and is very hard to spoof.
#
# The KILL_RUN_CMD_FIRST value should be set to "1" to force the command 
# to run *before* the blocking occurs and should be set to "0" to make the 
# command run *after* the blocking has occurred. 
#
#KILL_RUN_CMD_FIRST = "0"
#
#
#KILL_RUN_CMD="/some/path/here/script $TARGET$ $PORT$"


#####################
# Scan trigger value#
#####################
# Enter in the number of port connects you will allow before an 
# alarm is given. The default is 0 which will react immediately.
# A value of 1 or 2 will reduce false alarms. Anything higher is 
# probably not necessary. This value must always be specified, but
# generally can be left at 0. 
#
# NOTE: If you are using the advanced detection option you need to
# be careful that you don't make a hair trigger situation. Because
# Advanced mode will react for *any* host connecting to a non-used
# below your specified range, you have the opportunity to really 
# break things. (i.e someone innocently tries to connect to you via 
# SSL [TCP port 443] and you immediately block them). Some of you
# may even want this though. Just be careful.
#
SCAN_TRIGGER="0"

######################
# Port Banner Section#
######################
#
# Enter text in here you want displayed to a person tripping the PortSentry.
# I *don't* recommend taunting the person as this will aggravate them.
# Leave this commented out to disable the feature
#
# Stealth scan detection modes don't use this feature
#
#PORT_BANNER="** UNAUTHORIZED ACCESS PROHIBITED *** YOUR CONNECTION ATTEMPT HAS BEEN LOGGED. GO AWAY."

# EOF