PFCTL(8) OpenBSD System Manager's Manual PFCTL(8)NAMEpfctl - control the packet filter (PF) device
SYNOPSISpfctl [-deghnqrvz] [-a anchor] [-D macro=value] [-F modifier] [-f file]
[-i interface] [-K host | network] [-k host | network | label | id]
[-L statefile] [-o level] [-p device] [-S statefile] [-s modifier
[-R id]] [-t table -T command [address ...]] [-x level]
DESCRIPTION
The pfctl utility communicates with the packet filter device using the
ioctl interface described in pf(4). It allows ruleset and parameter
configuration and retrieval of status information from the packet filter.
Packet filtering restricts the types of packets that pass through network
interfaces entering or leaving the host based on filter rules as
described in pf.conf(5). The packet filter can also replace addresses
and ports of packets. Replacing source addresses and ports of outgoing
packets is called NAT (Network Address Translation) and is used to
connect an internal network (usually reserved address space) to an
external one (the Internet) by making all connections to external hosts
appear to come from the gateway. Replacing destination addresses and
ports of incoming packets is used to redirect connections to different
hosts and/or ports. A combination of both translations, bidirectional
NAT, is also supported. Translation rules are described in pf.conf(5).
When the variable pf is set to YES in rc.conf.local(8), the rule file
specified with the variable pf_rules is loaded automatically by the rc(8)
scripts and the packet filter is enabled.
The packet filter does not itself forward packets between interfaces.
Forwarding can be enabled by setting the sysctl(8) variables
net.inet.ip.forwarding and/or net.inet6.ip6.forwarding to 1. Set them
permanently in sysctl.conf(5).
The pfctl utility provides several commands. The options are as follows:
-a anchor
Apply flags -f, -F, and -s only to the rules in the specified
anchor. In addition to the main ruleset, pfctl can load and
manipulate additional rulesets by name, called anchors. The main
ruleset is the default anchor.
Anchors are referenced by name and may be nested, with the
various components of the anchor path separated by `/'
characters, similar to how file system hierarchies are laid out.
The last component of the anchor path is where ruleset operations
are performed.
Evaluation of anchor rules from the main ruleset is described in
pf.conf(5).
For example, the following will show all filter rules (see the -s
flag below) inside the anchor ``authpf/smith(1234)'', which would
have been created for user ``smith'' by authpf(8), PID 1234:
# pfctl-a "authpf/smith(1234)" -s rules
Private tables can also be put inside anchors, either by having
table statements in the pf.conf(5) file that is loaded in the
anchor, or by using regular table commands, as in:
# pfctl-a foo/bar -t mytable -T add 1.2.3.4 5.6.7.8
When a rule referring to a table is loaded in an anchor, the rule
will use the private table if one is defined, and then fall back
to the table defined in the main ruleset, if there is one. This
is similar to C rules for variable scope. It is possible to
create distinct tables with the same name in the global ruleset
and in an anchor, but this is often bad design and a warning will
be issued in that case.
By default, recursive inline printing of anchors applies only to
unnamed anchors specified inline in the ruleset. If the anchor
name is terminated with a `*' character, the -s flag will
recursively print all anchors in a brace delimited block. For
example the following will print the ``authpf'' ruleset
recursively:
# pfctl-a 'authpf/*' -sr
To print the main ruleset recursively, specify only `*' as the
anchor name:
# pfctl-a '*' -sr
-D macro=value
Define macro to be set to value on the command line. Overrides
the definition of macro in the ruleset.
-d Disable the packet filter.
-e Enable the packet filter.
-F modifier
Flush the filter parameters specified by modifier (may be
abbreviated):
-F queue Flush the queue rules.
-F rules Flush the filter rules.
-F states Flush the state table (NAT and filter).
-F Sources Flush the source tracking table.
-F info Flush the filter information (statistics that are
not bound to rules).
-F Tables Flush the tables.
-F osfp Flush the passive operating system fingerprints.
-F all Flush all of the above.
-f file
Replace the current ruleset with the rules contained in file.
This file may contain macros, tables, options, and normalization,
queueing, translation, and filtering rules. With the exception
of macros and tables, the statements must appear in that order.
-g Include output helpful for debugging.
-h Help.
-i interface
Restrict the operation to the given interface.
-K host | network
Kill all of the source tracking entries originating from the
specified host or network. A second -K host or -K network option
may be specified, which will kill all the source tracking entries
from the first host/network to the second.
-k host | network | label | id
Kill all of the state entries matching the specified host,
network, label, or id.
For example, to kill all of the state entries originating from
``host'':
# pfctl-k host
A second -k host or -k network option may be specified, which
will kill all the state entries from the first host/network to
the second. To kill all of the state entries from ``host1'' to
``host2'':
# pfctl-k host1 -k host2
To kill all states originating from 192.168.1.0/24 to
172.16.0.0/16:
# pfctl-k 192.168.1.0/24 -k 172.16.0.0/16
A network prefix length of 0 can be used as a wildcard. To kill
all states with the target ``host2'':
# pfctl-k 0.0.0.0/0 -k host2
It is also possible to kill states by rule label or state ID. In
this mode the first -k argument is used to specify the type of
the second argument. The following command would kill all states
that have been created from rules carrying the label ``foobar'':
# pfctl-k label -k foobar
To kill one specific state by its unique state ID (as shown by
pfctl-s state -vv), use the id modifier and as a second argument
the state ID and optional creator ID. To kill a state with ID
4823e84500000003 use:
# pfctl-k id -k 4823e84500000003
To kill a state with ID 4823e84500000018 created from a backup
firewall with hostid 00000002 use:
# pfctl-k id -k 4823e84500000018/2
-L statefile
Load pf states from the file specified by statefile.
-n Do not actually load rules, just parse them.
-o level
Control the ruleset optimizer, overriding any rule file settings.
-o none Disable the ruleset optimizer.
-o basic Enable basic ruleset optimizations. This is the
default behaviour.
-o profile Enable basic ruleset optimizations with profiling.
For further information on the ruleset optimizer, see pf.conf(5).
-p device
Use the device file device instead of the default /dev/pf.
-q Only print errors and warnings.
-r Perform reverse DNS lookups on states when displaying them.
-S statefile
Store the pf state table in the file specified by statefile.
-s modifier
Show the filter parameters specified by modifier (may be
abbreviated):
-s queue Show the currently loaded queue rules. When used
together with -v, per-queue statistics are also
shown. When used together with -v -v, pfctl will
loop and show updated queue statistics every five
seconds, including measured bandwidth and packets
per second.
-s rules Show the currently loaded filter rules. If -R id
is specified as well, only the rule with the
specified numeric ID is shown. When used together
with -v, the per-rule statistics (number of
evaluations, packets and bytes) are also shown.
Note that the ``skip step'' optimization done
automatically by the kernel will skip evaluation
of rules where possible. Packets passed
statefully are counted in the rule that created
the state (even though the rule isn't evaluated
more than once for the entire connection).
-s Anchors Show the currently loaded anchors directly
attached to the main ruleset. If -a anchor is
specified as well, the anchors loaded directly
below the given anchor are shown instead. If -v
is specified, all anchors attached under the
target anchor will be displayed recursively.
-s states Show the contents of the state table.
-s Sources Show the contents of the source tracking table.
-s info Show filter information (statistics and counters).
When used together with -v, source tracking
statistics are also shown.
-s labels Show per-rule statistics (label, evaluations,
packets total, bytes total, packets in, bytes in,
packets out, bytes out, state creations) of filter
rules with labels, useful for accounting. If -R
id is specified as well, only the statistics for
the rule with the specified numeric ID are shown.
-s timeouts Show the current global timeouts.
-s memory Show the current pool memory hard limits.
-s Tables Show the list of tables.
-s osfp Show the list of operating system fingerprints.
-s Interfaces Show the list of interfaces and interface drivers
available to PF. When used together with -v, it
additionally lists which interfaces have skip
rules activated. When used together with -vv,
interface statistics are also shown. -i can be
used to select an interface or a group of
interfaces.
-s all Show all of the above, except for the lists of
interfaces and operating system fingerprints.
-T command [address ...]
Specify the command (may be abbreviated) to apply to the table.
Commands include:
-T kill Kill a table.
-T flush Flush all addresses of a table.
-T add Add one or more addresses in a table.
Automatically create a nonexisting table.
-T delete Delete one or more addresses from a table.
-T expire number
Delete addresses which had their statistics cleared
more than number seconds ago. For entries which
have never had their statistics cleared, number
refers to the time they were added to the table.
-T replace Replace the addresses of the table. Automatically
create a nonexisting table.
-T show Show the content (addresses) of a table.
-T test Test if the given addresses match a table.
-T zero Clear all the statistics of a table.
For the add, delete, replace, and test commands, the list of
addresses can be specified either directly on the command line
and/or in an unformatted text file, using the -f flag. Comments
starting with a `#' are allowed in the text file. With these
commands, the -v flag can also be used once or twice, in which
case pfctl will print the detailed result of the operation for
each individual address, prefixed by one of the following
letters:
A The address/network has been added.
C The address/network has been changed (negated).
D The address/network has been deleted.
M The address matches (test operation only).
X The address/network is duplicated and therefore ignored.
Y The address/network cannot be added/deleted due to
conflicting `!' attributes.
Z The address/network has been cleared (statistics).
Each table can maintain a set of counters that can be retrieved
using the -v flag of pfctl. For example, the following commands
define a wide open firewall which will keep track of packets
going to or coming from the OpenBSD FTP server. The following
commands configure the firewall and send 10 pings to the FTP
server:
# printf "table <test> counters { ftp.openbsd.org }\n \
pass out to <test>\n" | pfctl-f-
# ping -qc10 ftp.openbsd.org
We can now use the table show command to output, for each address
and packet direction, the number of packets and bytes that are
being passed or blocked by rules referencing the table. The time
at which the current accounting started is also shown with the
``Cleared'' line.
# pfctl-t test -vTshow
129.128.5.191
Cleared: Thu Feb 13 18:55:18 2003
In/Block: [ Packets: 0 Bytes: 0 ]
In/Pass: [ Packets: 10 Bytes: 840 ]
Out/Block: [ Packets: 0 Bytes: 0 ]
Out/Pass: [ Packets: 10 Bytes: 840 ]
Similarly, it is possible to view global information about the
tables by using the -v modifier twice and the -s Tables command.
This will display the number of addresses on each table, the
number of rules which reference the table, and the global packet
statistics for the whole table:
# pfctl-vvsTables
--a-r-C test
Addresses: 1
Cleared: Thu Feb 13 18:55:18 2003
References: [ Anchors: 0 Rules: 1 ]
Evaluations: [ NoMatch: 3496 Match: 1 ]
In/Block: [ Packets: 0 Bytes: 0 ]
In/Pass: [ Packets: 10 Bytes: 840 ]
In/XPass: [ Packets: 0 Bytes: 0 ]
Out/Block: [ Packets: 0 Bytes: 0 ]
Out/Pass: [ Packets: 10 Bytes: 840 ]
Out/XPass: [ Packets: 0 Bytes: 0 ]
As we can see here, only one packet - the initial ping request -
matched the table, but all packets passing as the result of the
state are correctly accounted for. Reloading the table(s) or
ruleset will not affect packet accounting in any way. The two
``XPass'' counters are incremented instead of the ``Pass''
counters when a ``stateful'' packet is passed but doesn't match
the table anymore. This will happen in our example if someone
flushes the table while the ping(8) command is running.
When used with a single -v, pfctl will only display the first
line containing the table flags and name. The flags are defined
as follows:
c For constant tables, which cannot be altered outside
pf.conf(5).
p For persistent tables, which don't get automatically killed
when no rules refer to them.
a For tables which are part of the active tableset. Tables
without this flag do not really exist, cannot contain
addresses, and are only listed if the -g flag is given.
i For tables which are part of the inactive tableset. This
flag can only be witnessed briefly during the loading of
pf.conf(5).
r For tables which are referenced (used) by rules.
h This flag is set when a table in the main ruleset is hidden
by one or more tables of the same name from anchors attached
below it.
C This flag is set when per-address counters are enabled on
the table.
-t table
Specify the name of the table.
-v Produce more verbose output. A second use of -v will produce
even more verbose output including ruleset warnings. See the
previous section for its effect on table commands.
-x level
Set the debug level, which limits the severity of log messages
printed by pf(4). This should be a keyword from the following
ordered list (highest to lowest): emerg, alert, crit, err,
warning, notice, info, and debug. These keywords correspond to
the similar (LOG_) values specified to the syslog(3) library
routine, and may be abbreviated on the command line.
-z Clear per-rule statistics.
FILES
/etc/pf.conf Packet filter rules file.
/etc/pf.os Passive operating system fingerprint database.
SEE ALSOpf(4), pf.conf(5), pf.os(5), sysctl.conf(5), authpf(8), ftp-proxy(8),
rc(8), rc.conf(8), sysctl(8)HISTORY
The pfctl program and the pf(4) filter mechanism first appeared in
OpenBSD 3.0.
OpenBSD 4.9 October 3, 2010 OpenBSD 4.9
