doc/sync/ftfw/conntrackd.conf - manifest_repos/conntrack-tools - Git at Google

 #
 # Synchronizer settings
 #
 Sync {
 	Mode FTFW {
 		#
 		# Size of the resend queue (in objects). This is the maximum
 		# number of objects that can be stored waiting to be confirmed
 		# via acknoledgment. If you keep this value low, the daemon
 		# will have less chances to recover state-changes under message
 		# omission. On the other hand, if you keep this value high,
 		# the daemon will consume more memory to store dead objects.
 		# Default is 131072 objects.
 		#
 		# ResendQueueSize 131072

 		#
 		# This parameter allows you to set an initial fixed timeout
 		# for the committed entries when this node goes from backup
 		# to primary. This mechanism provides a way to purge entries
 		# that were not recovered appropriately after the specified
 		# fixed timeout. If you set a low value, TCP entries in
 		# Established states with no traffic may hang. For example,
 		# an SSH connection without KeepAlive enabled. If not set,
 		# the daemon uses an approximate timeout value calculation
 		# mechanism. By default, this option is not set.
 		#
 		# CommitTimeout 180

 		#
 		# If the firewall replica goes from primary to backup,
 		# the conntrackd -t command is invoked in the script.
 		# This command schedules a flush of the table in N seconds.
 		# This is useful to purge the connection tracking table of
 		# zombie entries and avoid clashes with old entries if you
 		# trigger several consecutive hand-overs. Default is 60 seconds.
 		#
 		# PurgeTimeout 60

 		# Set the acknowledgement window size. If you decrease this
 		# value, the number of acknowlegdments increases. More
 		# acknowledgments means more overhead as conntrackd has to
 		# handle more control messages. On the other hand, if you
 		# increase this value, the resend queue gets more populated.
 		# This results in more overhead in the queue releasing.
 		# The following value is based on some practical experiments
 		# measuring the cycles spent by the acknowledgment handling
 		# with oprofile. If not set, default window size is 300.
 		#
 		# ACKWindowSize 300

 		#
 		# This clause allows you to disable the external cache. Thus,
 		# the state entries are directly injected into the kernel
 		# conntrack table. As a result, you save memory in user-space
 		# but you consume slots in the kernel conntrack table for
 		# backup state entries. Moreover, disabling the external cache
 		# means more CPU consumption. You need a Linux kernel
 		# >= 2.6.29 to use this feature. By default, this clause is
 		# set off. If you are installing conntrackd for first time,
 		# please read the user manual and I encourage you to consider
 		# using the fail-over scripts instead of enabling this option!
 		#
 		# DisableExternalCache Off
 	}

 	#
 	# Multicast IP and interface where messages are
 	# broadcasted (dedicated link). IMPORTANT: Make sure
 	# that iptables accepts traffic for destination
 	# 225.0.0.50, eg:
 	#
 	#	iptables -I INPUT -d 225.0.0.50 -j ACCEPT
 	#	iptables -I OUTPUT -d 225.0.0.50 -j ACCEPT
 	#
 	Multicast {
 		#
 		# Multicast address: The address that you use as destination
 		# in the synchronization messages. You do not have to add
 		# this IP to any of your existing interfaces. If any doubt,
 		# do not modify this value.
 		#
 		IPv4_address 225.0.0.50

 		#
 		# The multicast group that identifies the cluster. If any
 		# doubt, do not modify this value.
 		#
 		Group 3780

 		#
 		# IP address of the interface that you are going to use to
 		# send the synchronization messages. Remember that you must
 		# use a dedicated link for the synchronization messages.
 		#
 		IPv4_interface 192.168.100.100

 		#
 		# The name of the interface that you are going to use to
 		# send the synchronization messages.
 		#
 		Interface eth2

 		# The multicast sender uses a buffer to enqueue the packets
 		# that are going to be transmitted. The default size of this
 		# socket buffer is available at /proc/sys/net/core/wmem_default.
 		# This value determines the chances to have an overrun in the
 		# sender queue. The overrun results packet loss, thus, losing
 		# state information that would have to be retransmitted. If you
 		# notice some packet loss, you may want to increase the size
 		# of the sender buffer. The default size is usually around
 		# ~100 KBytes which is fairly small for busy firewalls.
 		#
 		SndSocketBuffer 1249280

 		# The multicast receiver uses a buffer to enqueue the packets
 		# that the socket is pending to handle. The default size of this
 		# socket buffer is available at /proc/sys/net/core/rmem_default.
 		# This value determines the chances to have an overrun in the
 		# receiver queue. The overrun results packet loss, thus, losing
 		# state information that would have to be retransmitted. If you
 		# notice some packet loss, you may want to increase the size of
 		# the receiver buffer. The default size is usually around
 		# ~100 KBytes which is fairly small for busy firewalls.
 		#
 		RcvSocketBuffer 1249280

 		#
 		# Enable/Disable message checksumming. This is a good
 		# property to achieve fault-tolerance. In case of doubt, do
 		# not modify this value.
 		#
 		Checksum on
 	}
 	#
 	# You can specify more than one dedicated link. Thus, if one dedicated
 	# link fails, conntrackd can fail-over to another. Note that adding
 	# more than one dedicated link does not mean that state-updates will
 	# be sent to all of them. There is only one active dedicated link at
 	# a given moment. The `Default' keyword indicates that this interface
 	# will be selected as the initial dedicated link. You can have
 	# up to 4 redundant dedicated links. Note: Use different multicast
 	# groups for every redundant link.
 	#
 	# Multicast Default {
 	#	IPv4_address 225.0.0.51
 	#	Group 3781
 	#	IPv4_interface 192.168.100.101
 	#	Interface eth3
 	#	# SndSocketBuffer 1249280
 	#	# RcvSocketBuffer 1249280
 	#	Checksum on
 	# }

 	#
 	# You can use Unicast UDP instead of Multicast to propagate events.
 	# Note that you cannot use unicast UDP and Multicast at the same
 	# time, you can only select one.
 	#
 	# UDP {
 		#
 		# UDP address that this firewall uses to listen to events.
 		#
 		# IPv4_address 192.168.2.100
 		#
 		# or you may want to use an IPv6 address:
 		#
 		# IPv6_address fe80::215:58ff:fe28:5a27

 		#
 		# Destination UDP address that receives events, ie. the other
 		# firewall's dedicated link address.
 		#
 		# IPv4_Destination_Address 192.168.2.101
 		#
 		# or you may want to use an IPv6 address:
 		#
 		# IPv6_Destination_Address fe80::2d0:59ff:fe2a:775c

 		#
 		# UDP port used
 		#
 		# Port 3780

 		#
 		# The name of the interface that you are going to use to
 		# send the synchronization messages.
 		#
 		# Interface eth2

 		#
 		# The sender socket buffer size
 		#
 		# SndSocketBuffer 1249280

 		#
 		# The receiver socket buffer size
 		#
 		# RcvSocketBuffer 1249280

 		#
 		# Enable/Disable message checksumming.
 		#
 		# Checksum on
 	# }

 	#
 	# Other unsorted options that are related to the synchronization.
 	#
 	# Options {
 		#
 		# TCP state-entries have window tracking disabled by default,
 		# you can enable it with this option. As said, default is off.
 		# This feature requires a Linux kernel >= 2.6.36.
 		#
 		# TCPWindowTracking Off

 		# Set this option on if you want to enable the synchronization
 		# of expectations. You have to specify the list of helpers that
 		# you want to enable. Default is off. This feature requires
 		# a Linux kernel >= 3.5.
 		#
 		# ExpectationSync {
 		#	ftp
 		#	ras
 		#	q.931
 		#	h.245
 		#	sip
 		# }
 		#
 		# You can use this alternatively:
 		#
 		# ExpectationSync On
 		#
 		# If you want to synchronize expectations of all helpers.
 	# }
 }

 #
 # General settings
 #
 General {
 	#
 	# Enable systemd support. If conntrackd is compiled with the proper
 	# configuration, you can use a systemd service unit of Type=notify
 	# and use conntrackd with systemd watchdog as well.
 	# Default is: off
 	#
 	#Systemd on

 	#
 	# Set the nice value of the daemon, this value goes from -20
 	# (most favorable scheduling) to 19 (least favorable). Using a
 	# very low value reduces the chances to lose state-change events.
 	# Default is 0 but this example file sets it to most favourable
 	# scheduling as this is generally a good idea. See man nice(1) for
 	# more information.
 	#
 	Nice -20

 	#
 	# Select a different scheduler for the daemon, you can select between
 	# RR and FIFO and the process priority (minimum is 0, maximum is 99).
 	# See man sched_setscheduler(2) for more information. Using a RT
 	# scheduler reduces the chances to overrun the Netlink buffer.
 	#
 	# Scheduler {
 	#	Type FIFO
 	#	Priority 99
 	# }

 	#
 	# Number of buckets in the cache hashtable. The bigger it is,
 	# the closer it gets to O(1) at the cost of consuming more memory.
 	# Read some documents about tuning hashtables for further reference.
 	#
 	HashSize 32768

 	#
 	# Maximum number of conntracks, it should be double of:
 	# $ cat /proc/sys/net/netfilter/nf_conntrack_max
 	# since the daemon may keep some dead entries cached for possible
 	# retransmission during state synchronization.
 	#
 	HashLimit 131072

 	#
 	# Logfile: on (/var/log/conntrackd.log), off, or a filename
 	# Default: off
 	#
 	LogFile on

 	#
 	# Syslog: on, off or a facility name (daemon (default) or local0..7)
 	# Default: off
 	#
 	#Syslog on

 	#
 	# Lockfile
 	#
 	LockFile /var/lock/conntrack.lock

 	#
 	# Unix socket configuration
 	#
 	UNIX {
 		Path /var/run/conntrackd.ctl
 		Backlog 20
 	}

 	#
 	# Netlink event socket buffer size. If you do not specify this clause,
 	# the default buffer size value in /proc/net/core/rmem_default is
 	# used. This default value is usually around 100 Kbytes which is
 	# fairly small for busy firewalls. This leads to event message dropping
 	# and high CPU consumption. This example configuration file sets the
 	# size to 2 MBytes to avoid this sort of problems.
 	#
 	NetlinkBufferSize 2097152

 	#
 	# The daemon doubles the size of the netlink event socket buffer size
 	# if it detects netlink event message dropping. This clause sets the
 	# maximum buffer size growth that can be reached. This example file
 	# sets the size to 8 MBytes.
 	#
 	NetlinkBufferSizeMaxGrowth 8388608

 	#
 	# If the daemon detects that Netlink is dropping state-change events,
 	# it automatically schedules a resynchronization against the Kernel
 	# after 30 seconds (default value). Resynchronizations are expensive
 	# in terms of CPU consumption since the daemon has to get the full
 	# kernel state-table and purge state-entries that do not exist anymore.
 	# Be careful of setting a very small value here. You have the following
 	# choices: On (enabled, use default 30 seconds value), Off (disabled)
 	# or Value (in seconds, to set a specific amount of time). If not
 	# specified, the daemon assumes that this option is enabled.
 	#
 	# NetlinkOverrunResync On

 	#
 	# If you want reliable event reporting over Netlink, set on this
 	# option. If you set on this clause, it is a good idea to set off
 	# NetlinkOverrunResync. This option is off by default and you need
 	# a Linux kernel >= 2.6.31.
 	#
 	# NetlinkEventsReliable Off

 	#
 	# By default, the daemon receives state updates following an
 	# event-driven model. You can modify this behaviour by switching to
 	# polling mode with the PollSecs clause. This clause tells conntrackd
 	# to dump the states in the kernel every N seconds. With regards to
 	# synchronization mode, the polling mode can only guarantee that
 	# long-lifetime states are recovered. The main advantage of this method
 	# is the reduction in the state replication at the cost of reducing the
 	# chances of recovering connections.
 	#
 	# PollSecs 15

 	#
 	# The daemon prioritizes the handling of state-change events coming
 	# from the core. With this clause, you can set the maximum number of
 	# state-change events (those coming from kernel-space) that the daemon
 	# will handle after which it will handle other events coming from the
 	# network or userspace. A low value improves interactivity (in terms of
 	# real-time behaviour) at the cost of extra CPU consumption.
 	# Default (if not set) is 100.
 	#
 	# EventIterationLimit 100

 	#
 	# Event filtering: This clause allows you to filter certain traffic,
 	# There are currently three filter-sets: Protocol, Address and
 	# State. The filter is attached to an action that can be: Accept or
 	# Ignore. Thus, you can define the event filtering policy of the
 	# filter-sets in positive or negative logic depending on your needs.
 	# You can select if conntrackd filters the event messages from
 	# user-space or kernel-space. The kernel-space event filtering
 	# saves some CPU cycles by avoiding the copy of the event message
 	# from kernel-space to user-space. The kernel-space event filtering
 	# is prefered, however, you require a Linux kernel >= 2.6.29 to
 	# filter from kernel-space. If you want to select kernel-space
 	# event filtering, use the keyword 'Kernelspace' instead of
 	# 'Userspace'.
 	#
 	Filter From Userspace {
 		#
 		# Accept only certain protocols: You may want to replicate
 		# the state of flows depending on their layer 4 protocol.
 		#
 		Protocol Accept {
 			TCP
 			SCTP
 			DCCP
 			# UDP
 			# ICMP # This requires a Linux kernel >= 2.6.31
 			# IPv6-ICMP # This requires a Linux kernel >= 2.6.31
 		}

 		#
 		# Ignore traffic for a certain set of IP's: Usually all the
 		# IP assigned to the firewall since local traffic must be
 		# ignored, only forwarded connections are worth to replicate.
 		# Note that these values depends on the local IPs that are
 		# assigned to the firewall.
 		#
 		Address Ignore {
 			IPv4_address 127.0.0.1 # loopback
 			IPv4_address 192.168.0.100 # virtual IP 1
 			IPv4_address 192.168.1.100 # virtual IP 2
 			IPv4_address 192.168.0.1
 			IPv4_address 192.168.1.1
 			IPv4_address 192.168.100.100 # dedicated link ip
 			#
 			# You can also specify networks in format IP/cidr.
 			# IPv4_address 192.168.0.0/24
 			#
 			# You can also specify an IPv6 address
 			# IPv6_address ::1
 		}

 		#
 		# Uncomment this line below if you want to filter by flow state.
 		# This option introduces a trade-off in the replication: it
 		# reduces CPU consumption at the cost of having lazy backup
 		# firewall replicas. The existing TCP states are: SYN_SENT,
 		# SYN_RECV, ESTABLISHED, FIN_WAIT, CLOSE_WAIT, LAST_ACK,
 		# TIME_WAIT, CLOSED, LISTEN.
 		#
 		# State Accept {
 		#	ESTABLISHED CLOSED TIME_WAIT CLOSE_WAIT for TCP
 		# }
 	}
 }
	#
	# Synchronizer settings
	#
	Sync {
	Mode FTFW {
	#
	# Size of the resend queue (in objects). This is the maximum
	# number of objects that can be stored waiting to be confirmed
	# via acknoledgment. If you keep this value low, the daemon
	# will have less chances to recover state-changes under message
	# omission. On the other hand, if you keep this value high,
	# the daemon will consume more memory to store dead objects.
	# Default is 131072 objects.
	#
	# ResendQueueSize 131072

	#
	# This parameter allows you to set an initial fixed timeout
	# for the committed entries when this node goes from backup
	# to primary. This mechanism provides a way to purge entries
	# that were not recovered appropriately after the specified
	# fixed timeout. If you set a low value, TCP entries in
	# Established states with no traffic may hang. For example,
	# an SSH connection without KeepAlive enabled. If not set,
	# the daemon uses an approximate timeout value calculation
	# mechanism. By default, this option is not set.
	#
	# CommitTimeout 180

	#
	# If the firewall replica goes from primary to backup,
	# the conntrackd -t command is invoked in the script.
	# This command schedules a flush of the table in N seconds.
	# This is useful to purge the connection tracking table of
	# zombie entries and avoid clashes with old entries if you
	# trigger several consecutive hand-overs. Default is 60 seconds.
	#
	# PurgeTimeout 60

	# Set the acknowledgement window size. If you decrease this
	# value, the number of acknowlegdments increases. More
	# acknowledgments means more overhead as conntrackd has to
	# handle more control messages. On the other hand, if you
	# increase this value, the resend queue gets more populated.
	# This results in more overhead in the queue releasing.
	# The following value is based on some practical experiments
	# measuring the cycles spent by the acknowledgment handling
	# with oprofile. If not set, default window size is 300.
	#
	# ACKWindowSize 300

	#
	# This clause allows you to disable the external cache. Thus,
	# the state entries are directly injected into the kernel
	# conntrack table. As a result, you save memory in user-space
	# but you consume slots in the kernel conntrack table for
	# backup state entries. Moreover, disabling the external cache
	# means more CPU consumption. You need a Linux kernel
	# >= 2.6.29 to use this feature. By default, this clause is
	# set off. If you are installing conntrackd for first time,
	# please read the user manual and I encourage you to consider
	# using the fail-over scripts instead of enabling this option!
	#
	# DisableExternalCache Off
	}

	#
	# Multicast IP and interface where messages are
	# broadcasted (dedicated link). IMPORTANT: Make sure
	# that iptables accepts traffic for destination
	# 225.0.0.50, eg:
	#
	# iptables -I INPUT -d 225.0.0.50 -j ACCEPT
	# iptables -I OUTPUT -d 225.0.0.50 -j ACCEPT
	#
	Multicast {
	#
	# Multicast address: The address that you use as destination
	# in the synchronization messages. You do not have to add
	# this IP to any of your existing interfaces. If any doubt,
	# do not modify this value.
	#
	IPv4_address 225.0.0.50

	#
	# The multicast group that identifies the cluster. If any
	# doubt, do not modify this value.
	#
	Group 3780

	#
	# IP address of the interface that you are going to use to
	# send the synchronization messages. Remember that you must
	# use a dedicated link for the synchronization messages.
	#
	IPv4_interface 192.168.100.100

	#
	# The name of the interface that you are going to use to
	# send the synchronization messages.
	#
	Interface eth2

	# The multicast sender uses a buffer to enqueue the packets
	# that are going to be transmitted. The default size of this
	# socket buffer is available at /proc/sys/net/core/wmem_default.
	# This value determines the chances to have an overrun in the
	# sender queue. The overrun results packet loss, thus, losing
	# state information that would have to be retransmitted. If you
	# notice some packet loss, you may want to increase the size
	# of the sender buffer. The default size is usually around
	# ~100 KBytes which is fairly small for busy firewalls.
	#
	SndSocketBuffer 1249280

	# The multicast receiver uses a buffer to enqueue the packets
	# that the socket is pending to handle. The default size of this
	# socket buffer is available at /proc/sys/net/core/rmem_default.
	# This value determines the chances to have an overrun in the
	# receiver queue. The overrun results packet loss, thus, losing
	# state information that would have to be retransmitted. If you
	# notice some packet loss, you may want to increase the size of
	# the receiver buffer. The default size is usually around
	# ~100 KBytes which is fairly small for busy firewalls.
	#
	RcvSocketBuffer 1249280

	#
	# Enable/Disable message checksumming. This is a good
	# property to achieve fault-tolerance. In case of doubt, do
	# not modify this value.
	#
	Checksum on
	}
	#
	# You can specify more than one dedicated link. Thus, if one dedicated
	# link fails, conntrackd can fail-over to another. Note that adding
	# more than one dedicated link does not mean that state-updates will
	# be sent to all of them. There is only one active dedicated link at
	# a given moment. The `Default' keyword indicates that this interface
	# will be selected as the initial dedicated link. You can have
	# up to 4 redundant dedicated links. Note: Use different multicast
	# groups for every redundant link.
	#
	# Multicast Default {
	# IPv4_address 225.0.0.51
	# Group 3781
	# IPv4_interface 192.168.100.101
	# Interface eth3
	# # SndSocketBuffer 1249280
	# # RcvSocketBuffer 1249280
	# Checksum on
	# }

	#
	# You can use Unicast UDP instead of Multicast to propagate events.
	# Note that you cannot use unicast UDP and Multicast at the same
	# time, you can only select one.
	#
	# UDP {
	#
	# UDP address that this firewall uses to listen to events.
	#
	# IPv4_address 192.168.2.100
	#
	# or you may want to use an IPv6 address:
	#
	# IPv6_address fe80::215:58ff:fe28:5a27

	#
	# Destination UDP address that receives events, ie. the other
	# firewall's dedicated link address.
	#
	# IPv4_Destination_Address 192.168.2.101
	#
	# or you may want to use an IPv6 address:
	#
	# IPv6_Destination_Address fe80::2d0:59ff:fe2a:775c

	#
	# UDP port used
	#
	# Port 3780

	#
	# The name of the interface that you are going to use to
	# send the synchronization messages.
	#
	# Interface eth2

	#
	# The sender socket buffer size
	#
	# SndSocketBuffer 1249280

	#
	# The receiver socket buffer size
	#
	# RcvSocketBuffer 1249280

	#
	# Enable/Disable message checksumming.
	#
	# Checksum on
	# }

	#
	# Other unsorted options that are related to the synchronization.
	#
	# Options {
	#
	# TCP state-entries have window tracking disabled by default,
	# you can enable it with this option. As said, default is off.
	# This feature requires a Linux kernel >= 2.6.36.
	#
	# TCPWindowTracking Off

	# Set this option on if you want to enable the synchronization
	# of expectations. You have to specify the list of helpers that
	# you want to enable. Default is off. This feature requires
	# a Linux kernel >= 3.5.
	#
	# ExpectationSync {
	# ftp
	# ras
	# q.931
	# h.245
	# sip
	# }
	#
	# You can use this alternatively:
	#
	# ExpectationSync On
	#
	# If you want to synchronize expectations of all helpers.
	# }
	}

	#
	# General settings
	#
	General {
	#
	# Enable systemd support. If conntrackd is compiled with the proper
	# configuration, you can use a systemd service unit of Type=notify
	# and use conntrackd with systemd watchdog as well.
	# Default is: off
	#
	#Systemd on

	#
	# Set the nice value of the daemon, this value goes from -20
	# (most favorable scheduling) to 19 (least favorable). Using a
	# very low value reduces the chances to lose state-change events.
	# Default is 0 but this example file sets it to most favourable
	# scheduling as this is generally a good idea. See man nice(1) for
	# more information.
	#
	Nice -20

	#
	# Select a different scheduler for the daemon, you can select between
	# RR and FIFO and the process priority (minimum is 0, maximum is 99).
	# See man sched_setscheduler(2) for more information. Using a RT
	# scheduler reduces the chances to overrun the Netlink buffer.
	#
	# Scheduler {
	# Type FIFO
	# Priority 99
	# }

	#
	# Number of buckets in the cache hashtable. The bigger it is,
	# the closer it gets to O(1) at the cost of consuming more memory.
	# Read some documents about tuning hashtables for further reference.
	#
	HashSize 32768

	#
	# Maximum number of conntracks, it should be double of:
	# $ cat /proc/sys/net/netfilter/nf_conntrack_max
	# since the daemon may keep some dead entries cached for possible
	# retransmission during state synchronization.
	#
	HashLimit 131072

	#
	# Logfile: on (/var/log/conntrackd.log), off, or a filename
	# Default: off
	#
	LogFile on

	#
	# Syslog: on, off or a facility name (daemon (default) or local0..7)
	# Default: off
	#
	#Syslog on

	#
	# Lockfile
	#
	LockFile /var/lock/conntrack.lock

	#
	# Unix socket configuration
	#
	UNIX {
	Path /var/run/conntrackd.ctl
	Backlog 20
	}

	#
	# Netlink event socket buffer size. If you do not specify this clause,
	# the default buffer size value in /proc/net/core/rmem_default is
	# used. This default value is usually around 100 Kbytes which is
	# fairly small for busy firewalls. This leads to event message dropping
	# and high CPU consumption. This example configuration file sets the
	# size to 2 MBytes to avoid this sort of problems.
	#
	NetlinkBufferSize 2097152

	#
	# The daemon doubles the size of the netlink event socket buffer size
	# if it detects netlink event message dropping. This clause sets the
	# maximum buffer size growth that can be reached. This example file
	# sets the size to 8 MBytes.
	#
	NetlinkBufferSizeMaxGrowth 8388608

	#
	# If the daemon detects that Netlink is dropping state-change events,
	# it automatically schedules a resynchronization against the Kernel
	# after 30 seconds (default value). Resynchronizations are expensive
	# in terms of CPU consumption since the daemon has to get the full
	# kernel state-table and purge state-entries that do not exist anymore.
	# Be careful of setting a very small value here. You have the following
	# choices: On (enabled, use default 30 seconds value), Off (disabled)
	# or Value (in seconds, to set a specific amount of time). If not
	# specified, the daemon assumes that this option is enabled.
	#
	# NetlinkOverrunResync On

	#
	# If you want reliable event reporting over Netlink, set on this
	# option. If you set on this clause, it is a good idea to set off
	# NetlinkOverrunResync. This option is off by default and you need
	# a Linux kernel >= 2.6.31.
	#
	# NetlinkEventsReliable Off

	#
	# By default, the daemon receives state updates following an
	# event-driven model. You can modify this behaviour by switching to
	# polling mode with the PollSecs clause. This clause tells conntrackd
	# to dump the states in the kernel every N seconds. With regards to
	# synchronization mode, the polling mode can only guarantee that
	# long-lifetime states are recovered. The main advantage of this method
	# is the reduction in the state replication at the cost of reducing the
	# chances of recovering connections.
	#
	# PollSecs 15

	#
	# The daemon prioritizes the handling of state-change events coming
	# from the core. With this clause, you can set the maximum number of
	# state-change events (those coming from kernel-space) that the daemon
	# will handle after which it will handle other events coming from the
	# network or userspace. A low value improves interactivity (in terms of
	# real-time behaviour) at the cost of extra CPU consumption.
	# Default (if not set) is 100.
	#
	# EventIterationLimit 100

	#
	# Event filtering: This clause allows you to filter certain traffic,
	# There are currently three filter-sets: Protocol, Address and
	# State. The filter is attached to an action that can be: Accept or
	# Ignore. Thus, you can define the event filtering policy of the
	# filter-sets in positive or negative logic depending on your needs.
	# You can select if conntrackd filters the event messages from
	# user-space or kernel-space. The kernel-space event filtering
	# saves some CPU cycles by avoiding the copy of the event message
	# from kernel-space to user-space. The kernel-space event filtering
	# is prefered, however, you require a Linux kernel >= 2.6.29 to
	# filter from kernel-space. If you want to select kernel-space
	# event filtering, use the keyword 'Kernelspace' instead of
	# 'Userspace'.
	#
	Filter From Userspace {
	#
	# Accept only certain protocols: You may want to replicate
	# the state of flows depending on their layer 4 protocol.
	#
	Protocol Accept {
	TCP
	SCTP
	DCCP
	# UDP
	# ICMP # This requires a Linux kernel >= 2.6.31
	# IPv6-ICMP # This requires a Linux kernel >= 2.6.31
	}

	#
	# Ignore traffic for a certain set of IP's: Usually all the
	# IP assigned to the firewall since local traffic must be
	# ignored, only forwarded connections are worth to replicate.
	# Note that these values depends on the local IPs that are
	# assigned to the firewall.
	#
	Address Ignore {
	IPv4_address 127.0.0.1 # loopback
	IPv4_address 192.168.0.100 # virtual IP 1
	IPv4_address 192.168.1.100 # virtual IP 2
	IPv4_address 192.168.0.1
	IPv4_address 192.168.1.1
	IPv4_address 192.168.100.100 # dedicated link ip
	#
	# You can also specify networks in format IP/cidr.
	# IPv4_address 192.168.0.0/24
	#
	# You can also specify an IPv6 address
	# IPv6_address ::1
	}

	#
	# Uncomment this line below if you want to filter by flow state.
	# This option introduces a trade-off in the replication: it
	# reduces CPU consumption at the cost of having lazy backup
	# firewall replicas. The existing TCP states are: SYN_SENT,
	# SYN_RECV, ESTABLISHED, FIN_WAIT, CLOSE_WAIT, LAST_ACK,
	# TIME_WAIT, CLOSED, LISTEN.
	#
	# State Accept {
	# ESTABLISHED CLOSED TIME_WAIT CLOSE_WAIT for TCP
	# }
	}
	}