#!@@PERL@@ -w =head1 NAME fw_conntrack - Plugin to monitor the number of tracked connections through a Linux 2.4/2.6 firewall =head1 CONFIGURATION This plugin must run with root privileges =head2 CONFIGURATION EXAMPLE @@CONFDIR@@/plugin-conf.d/global or other file in that dir must contain: [fw_*] user root =head1 NOTES ESTABLISHED+FIN_WAIT+TIME_WAIT+SYN_SENT+UDP are the most interesting connections. The total list also includes SYN_RECV, CLOSE, CLOSE_WAIT, LAST_ACK and LISTEN, but these were not (often) observed on my firewall. TOTAL is the total number of tracked connections. ASSURED and UNREPLIED connections are complementary subsets of ESTABLISHED. ASSURED is after ACK is seen after SYN_RECV. Therefore ASSURED is plotted but not UNREPLIED. Note that the plugin depends on the netfilter "conntrack" userspace tool. It comes from http://conntrack-tools.netfilter.org/ =head1 AUTHORS =over =item 2004.05.05: Initial version by Nicolai Langfeldt, Linpro AS, Oslo, Norway =item 2004.05.06: Enhanced to count NATed connections after input from Xavier on munin-users list =item 2011.09.23: Perl version by Alex Tomlins =back =head1 LICENSE GPL =head1 MAGIC MARKERS #%# family=auto #%# capabilities=autoconf =cut use strict; use Munin::Plugin; my $conntrack = '/usr/sbin/conntrack'; my $nf_conntrack_file = '/proc/net/nf_conntrack'; my $ip_conntrack_file = '/proc/net/ip_conntrack'; my @conntrack_max_files = qw( /proc/sys/net/nf_conntrack_max /proc/sys/net/netfilter/nf_conntrack_max /proc/sys/net/ipv4/ip_conntrack_max /proc/sys/net/ipv4/netfilter/ip_conntrack_max ); if ( defined($ARGV[0]) and $ARGV[0] eq "autoconf" ) { if ( -x $conntrack or -r $nf_conntrack_file or -r $ip_conntrack_file) { print "yes\n"; } else { print "no (command $conntrack or file $nf_conntrack_file or file $ip_conntrack_file not found)\n"; } exit 0; } if ( defined($ARGV[0]) and $ARGV[0] eq "config" ) { print < 0, 'FIN_WAIT' => 0, 'TIME_WAIT' => 0, 'SYN_SENT' => 0, 'UDP' => 0, 'ASSURED' => 0, 'NATTED' => 0, 'TOTAL' => 0 ); open CMD, "$command|"; while () { $state{'TOTAL'} ++; $state{'UDP'} ++ if /udp /; $state{'ASSURED'} ++ if /ASSURED/; if (/tcp \s*\d+\s+\d+\s+(\S+)/) { $state{$1} ++; } if (/src=(\S+)\s+dst=(\S+)\s+sport.*src=(\S+)\s+dst=(\S+)/) { $state{'NATTED'} ++ if $1 ne $4 or $2 ne $3; } } close CMD; print "established.value $state{'ESTABLISHED'}\n"; print "fin_wait.value $state{'FIN_WAIT'}\n"; print "time_wait.value $state{'TIME_WAIT'}\n"; print "syn_sent.value $state{'SYN_SENT'}\n"; print "udp.value $state{'UDP'}\n"; print "assured.value $state{'ASSURED'}\n"; print "nated.value $state{'NATTED'}\n"; print "total.value $state{'TOTAL'}\n";