Provided by: conntrackd_1.4.3-3_amd64 bug


       conntrackd - netfilter connection tracking user-space daemon


       conntrackd [options]


       conntrackd  is  the  user-space  daemon for the netfilter connection tracking system. This
       daemon synchronizes connection tracking states between several  replica  firewalls.  Thus,
       conntrackd  can be used to deploy highly available stateful firewalls. The daemon supports
       Primary-Backup and Multiprimary  setups.  The  daemon  can  also  be  used  as  statistics


       The options recognized by conntrackd can be divided into several different groups.

       These  options specify the particular operation mode in which conntrackd runs. Only one of
       them can be specified at any given time.

       -d     Run conntrackd in daemon mode.

       conntrackd can be used in client mode to request several information and operations  to  a
       running daemon

       -i [ct|expect]"
              Dump the internal cache, i.e. show local states

       -e [ct|expect]"
              Dump the external cache, i.e. show foreign states

       -x     Display  output  in  XML format. This option is only valid in combination with "-i"
              and "-e" parameters.

       -f [|internal|external]
              Flush the internal and/or external cache

       -F [ct|expect]
              Flush the kernel conntrack table (if you use a Linux kernel >= 2.6.29, this  option
              will not flush your internal and external cache).

       -c     Commit external cache to conntrack table.

       -B     Force  a  bulk  send  to  other  replica firewalls. With this command, you will ask
              conntrackd to send the state-entries that it owns to others.

       -n     Request resync with other node (only FT-FW and NOTRACK modes).

       -k     Kill the daemon

       -s [|network|cache|runtime|link|rsqueue|process|queue|ct|expect]
              Dump statistics. If no parameter is passed, it displays the general statistics.  If
              "network" is passed as parameter it displays the networking statistics.  If "cache"
              is passed as parameter, it shows the extended cache statistics.   If  "runtime"  is
              passed  as  parameter, it shows the run-time statistics.  If "process" is passed as
              parameter, it shows existing child processes (if any).  If  "queue"  is  passed  as
              parameter,  it  shows queue statistics.  If "ct" is passed, it displays the general
              statistics.  If "expect" is passed as parameter, it shows expectation statistics.

       -R [ct|expect]
              Force a resync against the kernel connection tracking table

       -t     Reset the in-kernel timers (See PurgeTimeout clause)

       -v     Display version information.

       -h     Display help information.

       -C config file
              Configuration file path.

              The exit code is 0 for correct function. Errors cause an exit code of 1.


       The following example are illustrative, for a real use in a firewall fail-over, check  the script that comes with the sources.

       conntrackd -d
              Runs conntrackd in daemon and synchronization mode

       conntrackd -i
              Dumps the states held in the internal cache, i.e. those handled by this firewall

       conntrackd -e
              Dumps  the  states  held in the external cache, i.e. those handled by other replica

       conntrackd -c
              Commits the external cache into the kernel connection tracking system. This is used
              to inject the state so that the connections can be recovered during the failover.


       This  daemon  requires  a  Linux  kernel  version  >=  2.6.18. TCP window tracking support
       requires >= 2.6.22, otherwise you have to disable it. Helpers are fully supported since >=
       2.6.25,  however,  if  you  use any previous version, depending on the protocol helper and
       your setup (e.g. if you setup  performs  NAT  sequence  adjustments  or  not),  your  help
       connection may be successfully recovered.

       There  are several unsupported stateful iptables matches such as recent, connbytes and the
       quota matches which gather internal information to operate. Since  that  information  does
       not  belong to the domain of the connection tracking system, connections affected by those
       matches may not be fully recovered during the takeover.

       The daemon requires a Linux  kernel  version  >=  2.6.26  to  support  kernel-space  event
       filtering.  Otherwise, all the event filtering is done in userspace with the corresponding
       extra overhead. If you are not using the Filter clause in the configuration  file,  ignore
       this notice.


       During  the  0.9.9  development,  some important changes in the replication message format
       were  introduced.  Therefore,  conntrackd  >=  0.9.9  will  not  work  appropriately  with
       conntrackd  <=  0.9.8. This should not be a problem if you use the same conntrackd version
       in all the firewall replica nodes.




       Please, report them to  or  file  a  bug  in  Netfilter's
       bugzilla (


       Pablo Neira Ayuso wrote and maintains the conntrackd tool

       Please   send   bug  reports  to  <>.  Subscription  is

       Man page written by Pablo Neira Ayuso <>.

                                           Sep 25, 2014                             CONNTRACKD(8)