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1.0.1
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This patch updates the user manual on how to enable the expectation
support for conntrackd.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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This patch adds support to synchronize expectations between
firewalls. This addition aims to re-use as much as possible
of the existing infrastructure for stability reasons. The
expectation support has been tested with the FTP helper.
This extension requires libnetfilter_conntrack 1.0.0.
If this is the first time you're playing with conntrackd,
I *strongly* recommend you to get working setup of conntrackd
without expectation support before as described in the
documentation. Then, enabling expectation support is rather
easy.
To know more about expectations, if you're not familiar with them,
I suggest you to read:
"Netfilter's Connection Tracking System"
http://people.netfilter.org/pablo/docs/login.pdf
Reprinted from ;login: The Magazine of USENIX, vol. 31, no. 3
(Berkeley, CA: USENIX Association, 2006, pp40-45.)
In short, expectations allow one Linux firewall to filter multi-flow
traffic like FTP, SIP and H.323.
In my testbed, there are two firewalls in a primary-backup configuration
running keepalived. The use a couple of floating cluster IP address
(192.168.0.100 and 192.168.1.100) that are used by the client. These
firewalls protect one FTP server (192.168.1.2) that will be accessed by
one client.
In ASCII art, it looks like this:
192.168.0.100 192.168.1.100
eth1 eth2
fw-1
/ \ FTP
-- client ------ ------ server --
192.168.0.2 \ / 192.168.1.2
fw-2
This is the rule-set for the firewalls:
-A POSTROUTING -t nat -s 192.168.0.2/32 -d 192.168.1.2/32 -j SNAT --to-source 192.168.1.100
-A INPUT -p tcp -m tcp --dport 22 -j ACCEPT
-A INPUT -m state --state INVALID -j DROP
-A FORWARD -m state --state RELATED -j ACCEPT
-A FORWARD -i eth2 -m state --state ESTABLISHED -j ACCEPT
-A FORWARD -i eth1 -p tcp -m tcp --dport 21 --tcp-flags FIN,SYN,RST,ACK SYN -m state --state NEW -j ACCEPT
-A FORWARD -i eth1 -p tcp -m state --state ESTABLISHED -j ACCEPT
-A FORWARD -m state --state INVALID -j LOG --log-prefix "invalid: "
The following steps detail how to check that the expectation support
works fine for conntrackd:
1) You have to enable the expectation support in the configuration
file with the following option:
Sync {
...
Options {
ExpectationSync {
ftp
sip
h323
}
}
}
This enables expectation synchronization for the FTP, SIP and H.323 helpers.
You can alternatively use:
Sync {
...
Options {
ExpectationSync On
}
}
To enable expectation synchronization for all helpers.
2) Make sure you have loaded the FTP helper in both firewalls.
root@fw1# modprobe nf_conntrack_ftp
root@fw2# modprobe nf_conntrack_ftp
3) Switch to the client. Start one FTP control connection to one
server that is protected by the firewalls, enter passive mode:
(term-1) user@client$ nc 192.168.1.2 21
220 dummy FTP server
USER anonymous
331 Please specify the password.
PASS nothing
230 Login successful.
PASV
227 Entering Passive Mode (192,168,1,2,163,11).
This means that port 163*256+11=41739 will be used for the data
traffic. Read this if you are not familiar with the FTP protocol:
http://www.freefire.org/articles/ftpexample.php
3) Switch to fw-1 (primary) to check that the expectation is in the
internal cache.
root@fw1# conntrackd -i exp
proto=6 src=192.168.0.2 dst=192.168.1.2 sport=0 dport=41739 mask-src=255.255.255.255 mask-dst=255.255.255.255 sport=0 dport=65535 master-src=192.168.0.2 master-dst=192.168.1.2 sport=36390 dport=21 [active since 5s]
4) Switch to fw-2 (backup) to check that the expectation has been successfully
replicated.
root@fw2# conntrackd -e exp
proto=6 src=192.168.0.2 dst=192.168.1.2 sport=0 dport=41739 mask-src=255.255.255.255 mask-dst=255.255.255.255 sport=0 dport=65535 master-src=192.168.0.2 master-dst=192.168.1.2 sport=36390 dport=21 [active since 8s]
5) Make the primary firewall fw-1 fail. Now fw-2 becomes primary.
6) Switch to fw-2 (primary) to commit the external cache into the kernel.
root@fw2# conntrackd -c exp
The logs should display that the commit was successful:
root@fw2# tail -100f /var/log/conntrackd.log
[Wed Dec 7 22:16:31 2011] (pid=19195) [notice] committing external cache: expectations
[Wed Dec 7 22:16:31 2011] (pid=19195) [notice] Committed 1 new entries
[Wed Dec 7 22:16:31 2011] (pid=19195) [notice] commit has taken 0.000366 seconds
7) Switch to the client. Open a new terminal and connect to the port that
has been announced by the server:
(term-2) user@client$ nc -vvv 192.168.1.2 41739
(UNKNOWN) [192.168.1.2] 41739 (?) open
8) Switch to term-1 and ask for the file listing:
[...]
227 Entering Passive Mode (192,168,1,2,163,11).
LIST
9) Switch to term-2, it should display the listing. That means
everything has worked fine.
You may want to try disabling the expectation support and
repeating the steps to check that *it does not work* without
the state-synchronization.
You can also display expectation statistics by means of:
root@fwX# conntrackd -s exp
This update requires no changes in the primary-backup.sh script
that is used by the HA manager to interact with conntrackd. Thus,
we provide a backward compatible command line interface.
Regarding the Filter clause and expectations, we use the master
conntrack to filter expectation events. The filtering is performed
in user-space. No kernel-space filtering support for expectations
yet (this support should go in libnetfilter_conntrack at some
point).
This patch also includes support to disable caching and to allow
direct injection of expectations.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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This script is released under GPLv2+. Update copyright notice
as well.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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Remove reference which states that this is still under development
and refer to version 1.0.0.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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Now that we have fixed several aspects of the event filtering in
2.6.38, I reintroduce the documentation for this feature.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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Sorry, the iptables CT target is not yet ready for use until some
patches are pushed to the Linux kernel.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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This update adds to the documentation the following information:
* add reference to "Demystifying cluster-based fault-tolerant firewalls"
* add how-to disable the external cache
* add how-to disable the internal cache
* add how-to set the synchronization transport protocol
* document iptables CT target
* ask for sponsors to finish H323 and SIP support.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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This patch includes a minor documentation update with two new
questions in the FAQ.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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This patch fixes wrong Linux kernel requirements in the example
configuration files. We require a Linux kernel >= 2.6.36 instead
of >= 2.6.35 as the files suggest.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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This patch adds a comment on the TCPWindowTracking option to warn
that this will be supported since the Linux kernel 2.6.35.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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This patch fixes several minor nitpicks to support IPv6 failover:
* ICMPv6 type/code/id were missing in synchronization messages.
* The use of '-' as string in the configuration file was not allowed.
* Include example in configuration file under doc/.
Reported-by: Mohit Mehta <mohit.mehta@vyatta.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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This patch completes the documentation with the following discussion
that took place in the mailing list.
http://marc.info/?l=netfilter&m=127335152521674&w=2
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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This patch fixes the configuration file that includes an example of
the PollSecs clause in Stats. This is wrong since it should go in
the General clause.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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This patch adds a new option TCPWindowTracking that allows not
to disable TCP window tracking as it occurs by default.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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UDP filtering was broken during the addition of the UDP-based
synchronization protocol that was introduced in 0.9.14. This
patch fixes the problem.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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This patch documents the internal cache disabling feature that
is available for the NOTRACK mode. I have also added an example
on how to set up a TCP-based state-synchronization.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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This patch adds state-synchronization for ICMP. You SHOULD use a
Linux kernel >= 2.6.31, otherwise this patch can result in tons
of state-updates.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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In 49540362b2a25aadbaf25fd087414776aa5a67a8, we forgot to break lines
at 80 characters. This patch cleans up this issue.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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DisableExternalCache is supposed to be put in mode NOTRACK{} or
Mode FTFW{} statement.
Signed-off-by: Samuel Gauthier <samuel.gauthier@6wind.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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This patch adds support for TCP as protocol to replicate
state-changes between two daemons. Note that this only
makes sense with the notrack mode.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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This patch adds the clause `DisableExternalCache' that allows you
to disable the external cache and to directly inject the entries
into the kernel conntrack table. As a result, the CPU consumption
of conntrackd increases. This clause can only be used with the
FT-FW and the notrack synchronization modes, but not with the
alarm mode.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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This patch adds the missing support to filter IPv6 from kernel-space
by means of the BSF API that libnetfilter_conntrack provides.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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This patch adds the NetlinkEventsReliable clause, this is useful
to turn on reliable Netlink event delivery. This features
requires a Linux kernel >= 2.6.31.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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This is an update to commit 575fc906a302599cb9afeb136096dfd96bb57b17.
Signed-off-by: Jan Engelhardt <jengelh@medozas.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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This patch adds initial support for DCCP state replication.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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This patch adds initial support for SCTP state replication.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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With this patch, you can change the scheduler policy and priority
for conntrackd. Using a RT scheduler policy reduces the chances to
hit ENOBUFS in Netlink.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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This patch sets the most favourable nice value for conntrackd in the
default configuration files. This is generally a good idea to reduce
the chances to hit ENOBUFS.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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This patch fixes an EINVAL error returned by bind() when opening
an UDP server socket to propagate state-changes over the dedicated
link. This patch also includes the change of the example
configuration files in case that you want to use UDP over IPv6.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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This patch adds support for unicast UDP to the channel
infrastructure. With this patch, you can select UDP unicast to
propagate state-changes instead of multicast.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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Reported-by: Ralf <rm@amitrader.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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This patch adds two alias that removes an inconsistency in the
configuration file names. Now, the clauses that refers to Netlink
starts by the prefix "Netlink".
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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This patch reverts primary-backup-2.6.29-and-higher.sh. This script
is not safe for production enviroments until the commit phase
guarantees that the state-change propagation over netlink is
reliable. This script should be ready for 2.6.30 if the appropriate
kernel patches go into mainline in time.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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This patch updates the script to remark the fact that it should be
used with Linux kernel < 2.6.29. Moreover, it adds a bulk-update
command after the commit in the primary path to avoid any race
condition (the backup may request a resync while this primary
is still committing the entries with an empty internal cache).
This is hackish, but I think that this is the best way to do this
for systems running a Linux kernel < 2.6.29.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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This patch adds a new primary-backup.sh script for Linux kernels
>= 2.6.29. This script takes advantage of the user-space event
reporting that ctnetlink does since this kernel version.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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This patch unset ACKWindowSize since it already sets the clause
to its default value.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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This patch adds NetlinkOverrunResync. This option can be used to
set the amount of time after which the daemon resynchronizes itself
with the kernel state-table if it detects a Netlink overrun.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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This patch details a bit more the hashtable parameters. Moreover,
it increases the default size of the hashtable.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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This patch fixes a wrong use of 'from' instead of 'From' in the
example configuration files.
Reported-by: Yoann Juet <yoann.juet@univ-nantes.fr>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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This patch disables CommitTimeout by default. The daemon now uses
the approximate timeout calculation by default.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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This patch increases the default PurgeTimeout value to 60 seconds.
The former 15 seconds provides good real-time reaction in terms of
user-side expected behaviour, but it is too small if you trigger
random failure in a firewall cluster.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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This patch adds ResendQueueSize, which sets the number of objects
that can be stored in the resend queue waiting to be confirmed.
The ResendBufferSize clause has been deprecated.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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This patch adds the clause PollSecs that changes the normal
behaviour of conntrackd. With PollSecs set to > 0, conntrackd
polls every N seconds the entries.
This is the opposed behaviour of an event-driven behaviour but may
be useful for those that have really strong limitations in terms of
CPU consumption and want to perform a relaxed replication.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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This patch adds support for redundant dedicated links. You can add
a pool of dedicated links that can be used if the current active
fails.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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