MirBSD manpage: pfctl(8)

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

             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-

             -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-

             -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-
             -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

                                 # 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
                       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
             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
             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-

     -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

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