HardenedBSD/sbin/pfctl/pfctl.8

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.Dd July 23, 2024
.Dt PFCTL 8
.Os
.Sh NAME
.Nm pfctl
.Nd control the packet filter (PF) device
.Sh SYNOPSIS
.Nm pfctl
.Bk -words
.Op Fl AdeghMmNnOPqRrvz
.Op Fl a Ar anchor
.Oo Fl D Ar macro Ns =
.Ar value Oc
.Op Fl F Ar modifier
.Op Fl f Ar file
.Op Fl i Ar interface
.Op Fl K Ar host | network
.Xo
.Oo Fl k
.Ar host | network | label | id | gateway | nat
.Oc Xc
.Op Fl o Ar level
.Op Fl p Ar device
.Op Fl s Ar modifier
.Xo
.Oo Fl t Ar table
.Fl T Ar command
.Op Ar address ...
.Oc Xc
.Op Fl x Ar level
.Ek
.Sh DESCRIPTION
The
.Nm
utility communicates with the packet filter device using the
ioctl interface described in
.Xr pf 4 .
It allows ruleset and parameter configuration and retrieval of status
information from the packet filter.
.Pp
Packet filtering restricts the types of packets that pass through
network interfaces entering or leaving the host based on filter
rules as described in
.Xr 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
.Xr pf.conf 5 .
.Pp
When the variable
.Va pf
is set to
.Dv YES
in
.Xr rc.conf 5 ,
the rule file specified with the variable
.Va pf_rules
is loaded automatically by the
.Xr rc 8
scripts and the packet filter is enabled.
.Pp
The packet filter does not itself forward packets between interfaces.
Forwarding can be enabled by setting the
.Xr sysctl 8
variables
.Em net.inet.ip.forwarding
and/or
.Em net.inet6.ip6.forwarding
to 1.
Set them permanently in
.Xr sysctl.conf 5 .
.Pp
The
.Nm
utility provides several commands.
The options are as follows:
.Bl -tag -width Ds
.It Fl A
Load only the queue rules present in the rule file.
Other rules and options are ignored.
.It Fl a Ar anchor
Apply flags
.Fl f ,
.Fl F ,
and
.Fl s
only to the rules in the specified
.Ar anchor .
In addition to the main ruleset,
.Nm
can load and manipulate additional rulesets by name,
called anchors.
The main ruleset is the default anchor.
.Pp
Anchors are referenced by name and may be nested,
with the various components of the anchor path separated by
.Sq /
characters, similar to how file system hierarchies are laid out.
The last component of the anchor path is where ruleset operations are
performed.
.Pp
Evaluation of
.Ar anchor
rules from the main ruleset is described in
.Xr pf.conf 5 .
.Pp
For example, the following will show all filter rules (see the
.Fl s
flag below) inside the anchor
.Dq authpf/smith(1234) ,
which would have been created for user
.Dq smith
by
.Xr authpf 8 ,
PID 1234:
.Bd -literal -offset indent
# pfctl -a "authpf/smith(1234)" -s rules
.Ed
.Pp
Private tables can also be put inside anchors, either by having table
statements in the
.Xr pf.conf 5
file that is loaded in the anchor, or by using regular table commands, as in:
.Bd -literal -offset indent
# pfctl -a foo/bar -t mytable -T add 1.2.3.4 5.6.7.8
.Ed
.Pp
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.
.Pp
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
.Sq *
character, the
.Fl s
flag will recursively print all anchors in a brace delimited block.
For example the following will print the
.Dq authpf
ruleset recursively:
.Bd -literal -offset indent
# pfctl -a 'authpf/*' -sr
.Ed
.Pp
To print the main ruleset recursively, specify only
.Sq *
as the anchor name:
.Bd -literal -offset indent
# pfctl -a '*' -sr
.Ed
.It Fl D Ar macro Ns = Ns Ar value
Define
.Ar macro
to be set to
.Ar value
on the command line.
Overrides the definition of
.Ar macro
in the ruleset.
.It Fl d
Disable the packet filter.
.It Fl e
Enable the packet filter.
.It Fl F Ar modifier
Flush the filter parameters specified by
.Ar modifier
(may be abbreviated):
.Pp
.Bl -tag -width xxxxxxxxxxxx -compact
.It Fl F Cm nat
Flush the NAT rules.
.It Fl F Cm queue
Flush the queue rules.
.It Fl F Cm ethernet
Flush the Ethernet filter rules.
.It Fl F Cm rules
Flush the filter rules.
.It Fl F Cm states
Flush the state table (NAT and filter).
.It Fl F Cm Sources
Flush the source tracking table.
.It Fl F Cm info
Flush the filter information (statistics that are not bound to rules).
.It Fl F Cm Tables
Flush the tables.
.It Fl F Cm osfp
Flush the passive operating system fingerprints.
.It Fl F Cm all
Flush all of the above.
.El
.It Fl f Ar file
Load the rules contained in
.Ar file .
This
.Ar 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.
.It Fl g
Include output helpful for debugging.
.It Fl h
Help.
.It Fl i Ar interface
Restrict the operation to the given
.Ar interface .
.It Fl K Ar host | network
Kill all of the source tracking entries originating from the specified
.Ar host
or
.Ar network .
A second
.Fl K Ar host
or
.Fl K Ar network
option may be specified, which will kill all the source tracking
entries from the first host/network to the second.
.It Xo
.Fl k
.Ar host | network | label | id | gateway | nat
.Xc
Kill all of the state entries matching the specified
.Ar host ,
.Ar network ,
.Ar label ,
.Ar id ,
.Ar gateway,
or
.Ar nat.
.Pp
For example, to kill all of the state entries originating from
.Dq host :
.Pp
.Dl # pfctl -k host
.Pp
A second
.Fl k Ar host
or
.Fl k Ar 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
.Dq host1
to
.Dq host2 :
.Pp
.Dl # pfctl -k host1 -k host2
.Pp
To kill all states originating from 192.168.1.0/24 to 172.16.0.0/16:
.Pp
.Dl # pfctl -k 192.168.1.0/24 -k 172.16.0.0/16
.Pp
A network prefix length of 0 can be used as a wildcard.
To kill all states with the target
.Dq host2 :
.Pp
.Dl # pfctl -k 0.0.0.0/0 -k host2
.Pp
It is also possible to kill states by rule label or state ID.
In this mode the first
.Fl 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
.Dq foobar :
.Pp
.Dl # pfctl -k label -k foobar
.Pp
To kill one specific state by its unique state ID
(as shown by pfctl -s state -vv),
use the
.Ar id
modifier and as a second argument the state ID and optional creator ID.
To kill a state with ID 4823e84500000003 use:
.Pp
.Dl # pfctl -k id -k 4823e84500000003
.Pp
To kill a state with ID 4823e84500000018 created from a backup
firewall with hostid 00000002 use:
.Pp
.Dl # pfctl -k id -k 4823e84500000018/2
.Pp
It is also possible to kill states created from a rule with the route-to/reply-to
parameter set to route the connection through a particular gateway.
Note that rules routing via the default routing table (not via a route-to
rule) will have their rt_addr set as 0.0.0.0 or ::.
To kill all states using a gateway of 192.168.0.1 use:
.Pp
.Dl # pfctl -k gateway -k 192.168.0.1
.Pp
A network prefix length can also be specified.
To kill all states using a gateway in 192.168.0.0/24:
.Pp
.Dl # pfctl -k gateway -k 192.168.0.0/24
.Pp
States can also be killed based on their pre-NAT address:
.Pp
.Dl # pfctl -k nat -k 192.168.0.1
.Pp
.It Fl M
Kill matching states in the opposite direction (on other interfaces) when
killing states.
This applies to states killed using the -k option and also will apply to the
flush command when flushing states.
This is useful when an interface is specified when flushing states.
Example:
.Pp
.Dl # pfctl -M -i interface -Fs
.Pp
.It Fl m
Merge in explicitly given options without resetting those
which are omitted.
Allows single options to be modified without disturbing the others:
.Bd -literal -offset indent
# echo "set loginterface fxp0" | pfctl -mf -
.Ed
.It Fl N
Load only the NAT rules present in the rule file.
Other rules and options are ignored.
.It Fl n
Do not actually load rules, just parse them.
.It Fl O
Load only the options present in the rule file.
Other rules and options are ignored.
.It Fl o Ar level
Control the ruleset optimizer, overriding any rule file settings.
.Pp
.Bl -tag -width xxxxxxxxxxxx -compact
.It Fl o Cm none
Disable the ruleset optimizer.
.It Fl o Cm basic
Enable basic ruleset optimizations.
This is the default behaviour.
.It Fl o Cm profile
Enable basic ruleset optimizations with profiling.
.El
For further information on the ruleset optimizer, see
.Xr pf.conf 5 .
.It Fl P
Do not perform service name lookup for port specific rules,
instead display the ports numerically.
.It Fl p Ar device
Use the device file
.Ar device
instead of the default
.Pa /dev/pf .
.It Fl q
Only print errors and warnings.
.It Fl R
Load only the filter rules present in the rule file.
Other rules and options are ignored.
.It Fl r
Perform reverse DNS lookups on states when displaying them.
.It Fl s Ar modifier
Show the filter parameters specified by
.Ar modifier
(may be abbreviated):
.Pp
.Bl -tag -width xxxxxxxxxxxxx -compact
.It Fl s Cm nat
Show the currently loaded NAT rules.
.It Fl s Cm queue
Show the currently loaded queue rules.
When used together with
.Fl v ,
per-queue statistics are also shown.
When used together with
.Fl v v ,
.Nm
will loop and show updated queue statistics every five seconds, including
measured bandwidth and packets per second.
.It Fl s Cm ether
Show the currently loaded Ethernet rules.
When used together with
.Fl v ,
the per-rule statistics (number of evaluations,
packets, and bytes) are also shown.
.It Fl s Cm rules
Show the currently loaded filter rules.
When used together with
.Fl v ,
the per-rule statistics (number of evaluations,
packets, and bytes) are also shown.
Note that the
.Dq 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 is not evaluated more than once for the entire
connection).
.It Fl s Cm Anchors
Show the currently loaded anchors directly attached to the main ruleset.
If
.Fl a Ar anchor
is specified as well, the anchors loaded directly below the given
.Ar anchor
are shown instead.
If
.Fl v
is specified, all anchors attached under the target anchor will be
displayed recursively.
.It Fl s Cm states
Show the contents of the state table.
.It Fl s Cm Sources
Show the contents of the source tracking table.
.It Fl s Cm info
Show filter information (statistics and counters).
When used together with
.Fl v ,
source tracking statistics are also shown.
.It Fl s Cm Running
Show the running status and provide a non-zero exit status when disabled.
.It Fl s Cm 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.
.It Fl s Cm timeouts
Show the current global timeouts.
.It Fl s Cm memory
Show the current pool memory hard limits.
.It Fl s Cm Tables
Show the list of tables.
.It Fl s Cm osfp
Show the list of operating system fingerprints.
.It Fl s Cm Interfaces
Show the list of interfaces and interface drivers available to PF.
When used together with
.Fl v ,
it additionally lists which interfaces have skip rules activated.
When used together with
.Fl vv ,
interface statistics are also shown.
.Fl i
can be used to select an interface or a group of interfaces.
.It Fl s Cm all
Show all of the above, except for the lists of interfaces and operating
system fingerprints.
.El
.It Fl T Ar command Op Ar address ...
Specify the
.Ar command
(may be abbreviated) to apply to the table.
Commands include:
.Pp
.Bl -tag -width xxxxxxxxxxxx -compact
.It Fl T Cm kill
Kill a table.
.It Fl T Cm flush
Flush all addresses of a table.
.It Fl T Cm add
Add one or more addresses in a table.
Automatically create a nonexisting table.
.It Fl T Cm delete
Delete one or more addresses from a table.
.It Fl T Cm expire Ar number
Delete addresses which had their statistics cleared more than
.Ar number
seconds ago.
For entries which have never had their statistics cleared,
.Ar number
refers to the time they were added to the table.
.It Fl T Cm replace
Replace the addresses of the table.
Automatically create a nonexisting table.
.It Fl T Cm show
Show the content (addresses) of a table.
.It Fl T Cm test
Test if the given addresses match a table.
.It Fl T Cm zero
Clear all the statistics of a table.
.It Fl T Cm load
Load only the table definitions from
.Xr pf.conf 5 .
This is used in conjunction with the
.Fl f
flag, as in:
.Bd -literal -offset indent
# pfctl -Tl -f pf.conf
.Ed
.El
.Pp
For the
.Cm add ,
.Cm delete ,
.Cm replace ,
and
.Cm test
commands, the list of addresses can be specified either directly on the command
line and/or in an unformatted text file, using the
.Fl f
flag.
Comments starting with a
.Sq #
or
.Sq \;
are allowed in the text file.
With these commands, the
.Fl v
flag can also be used once or twice, in which case
.Nm
will print the
detailed result of the operation for each individual address, prefixed by
one of the following letters:
.Pp
.Bl -tag -width XXX -compact
.It A
The address/network has been added.
.It C
The address/network has been changed (negated).
.It D
The address/network has been deleted.
.It M
The address matches
.Po
.Cm test
operation only
.Pc .
.It X
The address/network is duplicated and therefore ignored.
.It Y
The address/network cannot be added/deleted due to conflicting
.Sq \&!
attributes.
.It Z
The address/network has been cleared (statistics).
.El
.Pp
Each table can maintain a set of counters that can be retrieved using the
.Fl v
flag of
.Nm .
For example, the following commands define a wide open firewall which will keep
track of packets going to or coming from the
.Ox
FTP server.
The following commands configure the firewall and send 10 pings to the FTP
server:
.Bd -literal -offset indent
# printf "table <test> counters { ftp.openbsd.org }\en \e
    pass out to <test>\en" | pfctl -f-
# ping -qc10 ftp.openbsd.org
.Ed
.Pp
We can now use the table
.Cm 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
.Dq Cleared
line.
.Bd -literal -offset indent
# 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      ]
.Ed
.Pp
Similarly, it is possible to view global information about the tables
by using the
.Fl v
modifier twice and the
.Fl s
.Cm 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:
.Bd -literal -offset indent
# 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        ]
.Ed
.Pp
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
.Dq XPass
counters are incremented instead of the
.Dq Pass
counters when a
.Dq stateful
packet is passed but does not match the table anymore.
This will happen in our example if someone flushes the table while the
.Xr ping 8
command is running.
.Pp
When used with a single
.Fl v ,
.Nm
will only display the first line containing the table flags and name.
The flags are defined as follows:
.Pp
.Bl -tag -width XXX -compact
.It c
For constant tables, which cannot be altered outside
.Xr pf.conf 5 .
.It p
For persistent tables, which do not get automatically killed when no rules
refer to them.
.It a
For tables which are part of the
.Em active
tableset.
Tables without this flag do not really exist, cannot contain addresses, and are
only listed if the
.Fl g
flag is given.
.It i
For tables which are part of the
.Em inactive
tableset.
This flag can only be witnessed briefly during the loading of
.Xr pf.conf 5 .
.It r
For tables which are referenced (used) by rules.
.It 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.
.It C
This flag is set when per-address counters are enabled on the table.
.El
.It Fl t Ar table
Specify the name of the table.
.It Fl v
Produce more verbose output.
A second use of
.Fl v
will produce even more verbose output including ruleset warnings.
See the previous section for its effect on table commands.
.It Fl x Ar level
Set the debug
.Ar level
(may be abbreviated) to one of the following:
.Pp
.Bl -tag -width xxxxxxxxxxxx -compact
.It Fl x Cm none
Do not generate debug messages.
.It Fl x Cm urgent
Generate debug messages only for serious errors.
.It Fl x Cm misc
Generate debug messages for various errors.
.It Fl x Cm loud
Generate debug messages for common conditions.
.El
.It Fl z
Clear per-rule statistics.
.El
.Sh FILES
.Bl -tag -width "/etc/pf.conf" -compact
.It Pa /etc/pf.conf
Packet filter rules file.
.It Pa /etc/pf.os
Passive operating system fingerprint database.
.El
.Sh SEE ALSO
.Xr pf 4 ,
.Xr pf.conf 5 ,
.Xr pf.os 5 ,
.Xr rc.conf 5 ,
.Xr services 5 ,
.Xr sysctl.conf 5 ,
.Xr authpf 8 ,
.Xr ftp-proxy 8 ,
.Xr rc 8 ,
.Xr sysctl 8
.Sh HISTORY
The
.Nm
program and the
.Xr pf 4
filter mechanism appeared in
.Ox 3.0 .
They first appeared in
.Fx 5.3
ported from the version in
.Ox 3.5