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PFCTL(8) BSD System Manager's Manual PFCTL(8) NAME pfctl -- control the packet filter (PF) and network address translation (NAT) device SYNOPSIS 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] DESCRIPTION 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 de- scribed 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 auto- matically 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 sta- tistics 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 in- terfaces. -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. Automati- cally 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 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 let- ters: 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 define a wide open firewall which will keep track of packets go- ing to or coming from the OpenBSD ftp server. The following com- mands 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 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 any- more. This will happen in our example if someone flushes the ta- ble 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 previ- ous section 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. FILES /etc/pf.conf Packet filter rules file. SEE ALSO pf(4), pf.conf(5), pf.os(5), sysctl.conf(5), 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. BSD November 20, 2002 BSD
NAME | SYNOPSIS | DESCRIPTION | FILES | SEE ALSO | HISTORY
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