pfctl

PFCTL(8)                     System Manager's Manual                    PFCTL(8)

NAME
     pfctl – control the packet filter (PF) and network address translation
     (NAT) device

SYNOPSIS
     pfctl [-AdeghmNnOqRrvz] [-a anchor] [-D macro= value] [-F modifier]
           [-f file] [-i interface] [-K host | network] [-k host | network]
           [-o level] [-p device] [-s modifier] [-t table -T command
           [address ...]] [-x level]

DESCRIPTION
     The pfctl utility communicates with the packet filter device.  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).

     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
             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).

             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.

     -X token
             Release the pf enable reference represented by the token passed.

     -e      Enable the packet filter.

     -E      Enable the packet filter and increment the pf enable reference
             count.

     -F modifier
             Flush the filter parameters specified by modifier (may be
             abbreviated):

             -F nat        Flush the NAT rules.
             -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
             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. Use of this option, could
             result in flushing of rules present in the main ruleset added by
             the system at startup. See /etc/pf.conf for further details.

     -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
             Kill all of the state entries originating from the specified host
             or network.  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.  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

             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

     -m      Merge in explicitly given options without resetting those which are
             omitted.  Allows single options to be modified without disturbing
             the others:

                   # echo "set loginterface fxp0" | pfctl -mf -

     -M      Enable port to name translation while displaying rule.

     -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.

     -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      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
             abbreviated):

             -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
                            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 References  Show pf-enable reference statistics (pid/name of
                            enabler, token, timestamp).
             -s labels      Show per-rule statistics (label, evaluations,
                            packets total, bytes total, packets in, bytes in,
                            packets out, bytes out) of filter rules with labels,
                            useful 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 -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.
             -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
             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 maintains 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> { 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-  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.

     -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.  A third use of -v will
             produce additional queue statistics related information.

     -w wait
             Show queue statistics at intervals of wait seconds.

     -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.

FILES
     /etc/pf.conf  Packet filter rules file.
     /etc/pf.os    Passive operating system fingerprint database.

SEE ALSO
     pf.conf(5), pf.os(5), sysctl.conf(5), ftp-proxy(8), sysctl(8)

HISTORY
     The pfctl program and the packet filter mechanism first appeared in
     OpenBSD 3.0.

macOS 12.1                        July 1, 2007                        macOS 12.1