NAME

npfctl — control NPF packet filter

SYNOPSIS

npfctl

command [arguments]

DESCRIPTION

The npfctl command can be used to control the NPF packet filter. For a description of NPF's configuration file, see npf.conf(5).

The first argument, command, specifies the action to take. Valid commands are:

start

Enable packet inspection using the currently loaded configuration, if any. Note that this command does not load or reload the configuration, or affect existing connections.

stop

Disable packet inspection. This command does not change the currently loaded configuration, or affect existing connections.

reload [path]

Load or reload configuration from file. The configuration file at /etc/npf.conf will be used unless a file is specified by path. All connections will be preserved during the reload, except those which will lose NAT policy due to removal. NAT policy is determined by the translation type and address. Note that change of filter criteria will not expire associated connections. The reload operation (i.e., replacing the ruleset, NAT policies and tables) is atomic.

flush

Flush configuration. That is, remove all rules, tables and expire all connections. This command does not disable packet inspection.

show

Show the current state and configuration. Syntax of printed configuration is for the user and may not match the npf.conf(5) syntax.

validate [path]

Validate the configuration file and the processed form. The configuration file at /etc/npf.conf will be used unless a file is specified by path.

rule name add <rule-syntax>

Add a rule to a dynamic ruleset specified by name. On success, returns a unique identifier which can be used to remove the rule with rem-id command. The identifier is alphanumeric string.

rule name rem <rule-syntax>

Remove a rule from a dynamic ruleset specified by name. This method uses SHA1 hash computed on a rule to identify it. Although very unlikely, it is subject to hash collisions. For a fully reliable and more efficient method, it is recommended to use rem-id command.

rule name rem-id <id>

Remove a rule specified by unique id from a dynamic ruleset specified by name.

rule name list

List all rules in the dynamic ruleset specified by name.

rule name flush

Remove all rules from the dynamic ruleset specified by name.

table tid add <addr/mask>

In table tid, add the IP address and optionally netmask, specified by <addr/mask>. Only tree-type tables support masks.

table tid rem <addr/mask>

In table tid, remove the IP address and optionally netmask, specified by <addr/mask>. Only tree-type tables support masks.

table tid test <addr>

Query the table tid for a specific IP address, specified by addr. If no mask is specified, a single host is assumed.

table tid list

List all entries in the currently loaded table specified by tid. This operation is expensive and should be used with caution.

save

Save the active configuration and a spanshot of the current connections. The data will be stored in the /var/db/npf.db file. Administrator may want to stop the packet inspection before saving.

load

Load the saved configuration file and the connections from the file. Note that any existing connections will be destroyed. Administrator may want to start packet inspection after the load.

stats

Print various statistics.

debug

Process the configuration file, print the byte-code of each rule and dump the raw configuration. This is primarily for developer use.

PERFORMANCE

Reloading the configuration is a relatively expensive operation. Therefore, frequent reloads should be avoided. Use of tables should be considered as an alternative design. See npf.conf(5) for details.

FILES

/dev/npf

control device

/etc/npf.conf

default configuration file

EXAMPLES

Starting the NPF packet filter:

# npfctl reload 
# npfctl start 
# npfctl show

Addition and removal of entries in the table whose ID is 2:

# npfctl table 2 add 10.0.0.1 
# npfctl table 2 rem 182.168.0.0/24

SEE ALSO

bpf(4), npf.conf(5), npf(7)

HISTORY

NPF first appeared in NetBSD 6.0.

AUTHORS

NPF was designed and implemented by Mindaugas Rasiukevicius.