NAME

       dnsdist - tool to balance DNS queries over downstream servers

SYNOPSIS

       dnsdist [OPTION]...  ADDRESS...

DESCRIPTION

       dnsdist  receives  DNS  queries  and  relays  them  to one or more downstream servers.  It
       subsequently sends back responses to the original requestor.

       dnsdist operates over TCP and UDP, and strives to deliver very high performance over both.

       Currently, queries are sent to the downstream server with the least  outstanding  queries.
       This effectively implies load balancing, making sure that slower servers get less queries.

       If  a  reply has not come in after a few seconds, it is removed from the queue, but in the
       short term, timeouts do cause a server to get less traffic.

       IPv4 and IPv6 operation can be mixed and matched, in other words, queries coming  in  over
       IPv6 could be forwarded to IPv4 and vice versa.

       dnsdist is scriptable in Lua, see the dnsdist documentation for more information on this.

SCOPE

       dnsdist  does  not  'think' about DNS, and does not perform any kind of caching, nor is it
       aware of the quality of the answers it is relaying.

       dnsdist assumes that each query leads to exactly one response, which is true for  all  DNS
       except for AXFR, which is therefore not supported.

       The  goal  for  dnsdist  is to remain simple.  If more powerful loadbalancing is required,
       dedicated hardware or software is recommended.  Linux Virtual Server for example is  often
       mentioned.

OPTIONS

       -a,--acl NETMASK
              Add NETMASK to the ACL.

       -C,--config FILE
              Load configuration from FILE.

       -c,--client
              Operate as a client, connect to dnsdist.

       -d,--daemon
              Operate as a daemon.

       -e,--execute CMD
              Connect to dnsdist and execute CMD.

       -h,--help
              Display a helpful message and exit.

       -l,--local ADDRESS
              Bind  to  ADDRESS,  Supply as many addresses (using multiple --local statements) to
              listen on as required.  Specify IPv4 as 0.0.0.0:53 and IPv6 as [::]:53.

       --supervised
              Run in foreground, but do not spawn a console.  Use  this  switch  to  run  dnsdist
              inside a supervisor (use with e.g.  systemd and daemontools).

       -p,--pidfile FILE
              Write a pidfile to FILE, works only with --daemon.

       -u,--uid UID
              Change the process user to UID after binding sockets.  UID can be a name or number.

       -g,--gid GID
              Change  the  process  group  to  GID  after  binding sockets.  GID Can be a name or
              number.

       -V,--version
              Show the dnsdist version and exit.

       ADDRESS
              Any number of downstream DNS servers, in the same syntax as used with --local.   If
              the port is not specified, 53 is used.

BUGS

       Right now, the TCP support has some rather arbitrary limits.

RESOURCES

       Website: http://dnsdist.org

AUTHORS

       PowerDNS.com BV.

                                               2013                                    DNSDIST(1)