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BLOCKLISTD.CONF(5) NetBSD File Formats Manual BLOCKLISTD.CONF(5)
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blocklistd.conf -- configuration file format for blocklistd
The blocklistd.conf file contains configuration entries for blocklistd(8)
in a fashion similar to inetd.conf(5). Only one entry per line is per-
mitted. Every entry must have all fields populated. Each field can be
separated by a tab or a space. Comments are denoted by a ``#'' at the
beginning of a line.
There are two kinds of configuration lines, local and remote. By
default, configuration lines are local, i.e. the address specified refers
to the addresses on the local machine. To switch to between local and
remote configuration lines you can specify the stanzas: ``[local]'' and
On local and remote lines ``*'' means use the default, or wildcard match.
In addition, for remote lines ``='' means use the values from the matched
local configuration line.
The first four fields, location, type, proto, and owner are used to match
the local or remote addresses, whereas the last 3 fields name, nfail, and
disable are used to modify the filtering action.
The first field denotes the location as an address, mask, and port. The
syntax for the location is:
The address can be an IPv4 address in numeric format, an IPv6 address in
numeric format and enclosed by square brackets, or an interface name.
Mask modifiers are not allowed on interfaces because interfaces can have
multiple addresses in different protocols where the mask has a different
The mask is always numeric, but the port can be either numeric or sym-
The second field is the socket type: stream, dgram, or numeric. The
third field is the protocol: tcp, udp, tcp6, udp6, or numeric. The
fourth field is the effective user (owner) of the daemon process report-
ing the event, either as a username or a userid.
The rest of the fields control the behavior of the filter.
The name field, is the name of the packet filter rule to be used. If the
name starts with a ``-'', then the default rulename is prepended to the
given name. If the name contains a ``/'', the remaining portion of the
name is interpreted as the mask to be applied to the address specified in
the rule, causing a single rule violation to block the entire subnet for
the configured prefix.
The nfail field contains the number of failed attempts before access is
blocked, defaulting to ``*'' meaning never, and the last field disable
specifies the amount of time since the last access that the blocking rule
should be active, defaulting to ``*'' meaning forever. The default unit
for disable is seconds, but one can specify suffixes for different units,
such as ``m'' for minutes ``h'' for hours and ``d'' for days.
Matching is done first by checking the local rules individually, in the
order of the most specific to the least specific. If a match is found,
then the remote rules are applied. The name, nfail, and disable fields
can be altered by the remote rule that matched.
The remote rules can be used for allowing specific addresses, changing
the mask size, the rule that the packet filter uses, the number of failed
attempts, or the block duration.
/etc/blocklistd.conf Configuration file.
# Block ssh, after 3 attempts for 6 hours on the bnx0 interface
# location type proto owner name nfail duration
bnx0:ssh * * * * 3 6h
# Never block 188.8.131.52
184.108.40.206:ssh * * * * * *
# For addresses coming from 220.127.116.11/16 block class C networks instead
# individual hosts, but keep the rest of the blocking parameters the same.
18.104.22.168/16:ssh * * * /24 = =
blocklistd.conf first appeared in NetBSD 7. FreeBSD support for
blocklistd.conf was implemented in FreeBSD 11.
NetBSD 10.99 May 18, 2020 NetBSD 10.99