PFCTL(8) BSD System Manager's Manual PFCTL(8)
pfctl - control the packet filter (PF) and network address translation
(NAT) device
pfctl [-AdeghNnOqRrvz] [-a anchor[:ruleset]] [-D macro=value]
[-F modifier] [-f file] [-i interface] [-k host] [-p device]
[-s modifier] [-T command [address ...]] [-t table] [-x level]
The pfctl utility communicates with the packet filter device using the
ioctl interface described in pf(4). It allows ruleset and parameter con-
figuration 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 pack-
ets 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 pack-
ets 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(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 Load only the queue rules present in the rule file. Other rules
and options are ignored.
-a anchor[:ruleset]
Apply flags -f, -F and -s only to the rules in the specified
anchor and optional named ruleset ruleset. In addition to the
main ruleset, pfctl can load and manipulate additional rulesets
by name. Named rulesets are attached at anchor points, which are
also referenced by name. Evaluation of anchor rules from the main
ruleset is described in pf.conf(5). For example, to show all
filter rules inside anchor foo:
# pfctl -a foo -s rules
Private tables can also be put inside subrulesets, either by hav-
ing 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 fallback
to the table defined in the main ruleset, if there is one. This
is similar to C rules for variables. 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 is-
sued in that case.
-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 abbre-
viated):
-F nat Flush the NAT rules.
-F queue Flush the queue rules.
-F rules Flush the filter rules.
-F state 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
Load 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
Kill all of the state entries originating from the specified
host. A second -k host option may be specified, which will kill
all the state entries from the first host to the second host. For
example, to kill all of the state entries originating from host:
# pfctl -k host
To kill all of the state entries from host1 to host2:
# pfctl -k host1 -k host2
-N Load only the NAT rules present in the rule file. Other rules and
options are ignored.
-n Do not actually load rules, just parse them.
-O Load only the options present in the rule file. Other rules and
options are ignored.
-p device
Use the device file device instead of the default /dev/pf.
-q Only print errors and warnings.
-R Load only the filter rules present in the rule file. Other rules
and options are ignored.
-r Perform reverse DNS lookups on states when displaying them.
-s modifier
Show the filter parameters specified by modifier (may be abbrevi-
ated):
-s nat Show the currently loaded NAT rules.
-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. 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 au-
tomatically 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. If -a anchor is
specified as well, the named rulesets currently
loaded in the specified anchor are shown instead.
-s state 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, bytes) of filter rules with labels, use-
ful for accounting.
-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 a double
-v, interface statistics are also shown. -i can be
used to select an interface or a group of inter-
faces.
-s all Show all of the above, except for the lists of in-
terfaces 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 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.
-T load Load only the table definitions from pf.conf(5).
This is used in conjunction with the -f flag, as
in:
# pfctl -Tl -f pf.conf
For the add, delete, replace and test commands, the list of ad-
dresses 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 com-
mands, 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 conflict-
ing "!" attribute.
Z The address/network has been cleared (statistics).
Each table maintains a set of counters that can be retrieved us-
ing the -v flag of pfctl. For example, the following commands de-
fine 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> { ftp.openbsd.org }\n \
pass out to <test> keep state\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 show Tables com-
mand. 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- 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 ru-
leset 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 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 flushed
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 ad-
dresses, 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 in sub-rulesets (an-
chors).
-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 previous sec-
tion for its effect on table commands.
-x level
Set the debug level (may be abbreviated) to one of the following:
-x none Don't generate debug messages.
-x urgent Generate debug messages only for serious errors.
-x misc Generate debug messages for various errors.
-x loud Generate debug messages for common conditions.
-z Clear per-rule statistics.
/etc/pf.conf Packet filter rules file.
pf(4), pf.conf(5), pf.os(5), sysctl.conf(5), ftp-proxy(8), rc(8),
rc.conf(8), sysctl(8)
The pfctl program and the pf(4) filter mechanism first appeared in
OpenBSD 3.0.
MirBSD #10-current November 20, 2002 4