CONNTRACKD(8)
NAME
conntrackd - netfilter connection tracking user-space daemon
SYNOPSIS
conntrackd [options]
DESCRIPTION
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 collector.
OPTIONS
- The options recognized by conntrackd can be divided into several different groups.
- MODES
- 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.
- CLIENT COMMANDS
- conntrackd can be used in client mode to request several information and operations to a running daemon
- -i Dump the internal cache, i.e. show local states
- -e Dump the external cache, i.e. show foreign states
- -x Display output in XML format. This option is only valid in com
bination with "-i" and "-e" parameters.
- -f [|internal|external]
Flush the internal and/or external cache
- -F Flush the kernel conntrack table (if you use a Linux kernel >=
2.6.29, this option will not flush your internal and external cache).
- -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.
- -k Kill the daemon
- -s [|network|cache|runtime|link|rsqueue|process|queue]
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.
- -R 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.
DIAGNOSTICS
The exit code is 0 for correct function. Errors cause an exit code of
1.
EXAMPLES
The following example are illustrative, for a real use in a firewall
fail-over, check the primary-backup.sh 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 firewalls
- 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.
DEPENDENCIES
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 kernelspace 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.
INCOMPATIBILITIES
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.
SEE ALSO
conntrack(8),iptables(8)
See http://conntrack-tools.netfilter.org
BUGS
Please, report them to netfilter-devel@vger.kernel.org or file a bug in
Netfilter's bugzilla (https://bugzilla.netfilter.org).
AUTHORS
Pablo Neira Ayuso wrote and maintains the conntrackd tool
Please send bug reports to <netfilter-devel@lists.netfilter.org>. Subscription is required.
- Man page written by Pablo Neira Ayuso <pablo@netfilter.org>.