NAME
blacklistd —
    block and release ports on demand to
    avoid DoS abuse
SYNOPSIS
blacklistd | 
    [-dfrv] [-C
      controlprog] [-c
      configfile] [-D
      dbfile] [-P
      sockpathsfile] [-R
      rulename] [-s
      sockpath] [-t
      timeout] | 
  
DESCRIPTION
blacklistd is a daemon similar to
  syslogd(8) that listens to sockets at paths specified in the
  sockpathsfile for notifications from other daemons about
  successful or failed connection attempts. If no such file is specified, then
  it only listens to the socket path specified by
  sockspath or if that is not specified to
  /var/run/blacklistd.sock. Each notification contains
  an (action, port, protocol, address, owner) tuple that identifies the remote
  connection and the action. This tuple is consulted against entries in
  configfile with syntax specified in
  blacklistd.conf(5). If an entry is matched, a state entry is
  created for that tuple. Each entry contains a number of tries limit and a
  duration.
If the action is “add” and the number of tries limit is reached, then a control script controlprog is invoked with arguments:
control add <rulename> <proto> <address> <mask> <port>
and should invoke a packet filter command to block the connection
    specified by the arguments. The rulename argument can
    be set from the command line (default blacklistd).
    The script could print a numerical id to stdout as a handle for the rule
    that can be used later to remove that connection, but that is not required
    as all information to remove the rule is kept.
If the action is “remove” Then the same control script is invoked as:
control remove <rulename> <proto> <address> <mask> <port> <id>
where id is the number returned from the “add” action.
blacklistd maintains a database of known
    connections in dbfile. On startup it reads entries
    from that file, and updates its internal state.
blacklistd checks the list of active
    entries every timeout seconds (default
    15) and removes entries and block rules using the
    control program as necessary.
The following options are available:
-Ccontrolprog- Use controlprog to communicate with the packet
      filter, usually /usr/libexec/blacklistd-helper.
      The following arguments are passed to the control program:
    
- action
 - The action to perform: 
add,rem, orflushto add, remove or flush a firewall rule. - name
 - The rule name.
 - protocol
 - The optional protocol name (can be empty):
          
tcp,tcp6,udp,udp6. - address
 - The IPv4 or IPv6 numeric address to be blocked or released.
 - mask
 - The numeric mask to be applied to the blocked or released address
 - port
 - The optional numeric port to be blocked (can be empty).
 - id
 - For packet filters that support removal of rules by rule identifier, the identifier of the rule to be removed. The add command is expected to return the rule identifier string to stdout.
 
 -cconfiguration- The name of the configuration file to read, usually /etc/blacklistd.conf.
 -Ddbfile- The Berkeley DB file where 
blacklistdstores its state, usually /var/run/blacklistd.db. -d- Normally, 
blacklistddisassociates itself from the terminal unless the-dflag is specified, in which case it stays in the foreground. -f- Truncate the state database and flush all the rules named
      rulename are deleted by invoking the control script
      as:
    
control flush <rulename>
 -Psockspathsfile- A file containing a list of pathnames, one per line that
      
blacklistdwill create sockets to listen to. This is useful for chrooted environments. -Rrulename- Specify the default rule name for the packet filter rules, usually
      
blacklistd. -r- Re-read the firewall rules from the internal database, then remove and re-add them. This helps for packet filters that do not retain state across reboots.
 -ssockpath- Add sockpath to the list of Unix sockets
      
blacklistdlistens to. -ttimeout- The interval in seconds 
blacklistdpolls the state file to update the rules. -v- Cause 
blacklistdto print diagnostic messages tostdoutinstead of syslogd(8). 
SIGNAL HANDLING
blacklistd deals with the following
    signals:
- HUP
 - Receipt of this signal causes 
blacklistdto re-read the configuration file. - INT, TERM & QUIT
 - These signals tell 
blacklistdto exit in an orderly fashion. - USR1
 - This signal tells 
blacklistdto increase the internal debugging level by 1. - USR2
 - This signal tells 
blacklistdto decrease the internal debugging level by 1. 
FILES
- /usr/libexec/blacklistd-helper
 - Shell script invoked to interface with the packet filter.
 - /etc/blacklistd.conf
 - Configuration file.
 - /var/db/blacklistd.db
 - Database of current connection entries.
 - /var/run/blacklistd.sock
 - Socket to receive connection notifications.
 
SEE ALSO
HISTORY
blacklistd first appeared in
    NetBSD 7. FreeBSD support
    for blacklistd was implemented in
    FreeBSD 11.
AUTHORS
Christos Zoulas