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COREDNS-BIND(7) 		 CoreDNS Plugins		 COREDNS-BIND(7)

NAME
     bind - overrides the host to which the server should bind.

DESCRIPTION
     Normally,	the  listener  binds to the wildcard host. However, you may want
     the listener to bind to another IP instead.

     If several addresses are provided, a listener will be open on each  of  the
     IP provided.

     Each  address has to be an IP or name of one of the interfaces of the host.
     Bind by interface name, binds to the IPs on that interface at the	time  of
     startup  or  reload (reload will happen with a SIGHUP or if the config file
     changes).

     If the given argument is an interface name, and that interface has  several
     IP addresses, CoreDNS will listen on all of the interface IP addresses (in-
     cluding IPv4 and IPv6).

SYNTAX
     In its basic form, a simple bind uses this syntax:

	    bind ADDRESS|IFACE	...

     You can also exclude some addresses with their IP address or interface name
     in expanded syntax:

	    bind ADDRESS|IFACE ... {
		except ADDRESS|IFACE ...
	    }

     *	 ADDRESS|IFACE is an IP address or interface name to bind to.  When sev-
	 eral  addresses  are  provided a listener will be opened on each of the
	 addresses. Please read the Description for more details.

     *	 except, excludes interfaces or IP addresses to bind to.  except  option
	 only excludes addresses for the current bind directive if multiple bind
	 directives are used in the same server block.

EXAMPLES
     To  make  your socket accessible only to that machine, bind to IP 127.0.0.1
     (localhost):

	    . {
		bind 127.0.0.1
	    }

     To allow processing DNS requests only local host  on  both  IPv4  and  IPv6
     stacks, use the syntax:

	    . {
		bind 127.0.0.1 ::1
	    }

     If  the configuration comes up with several bind plugins, all addresses are
     consolidated together: The following sample is equivalent to the preceding:

	    . {
		bind 127.0.0.1
		bind ::1
	    }

     The following server block, binds on  localhost  with  its  interface  name
     (both "127.0.0.1" and "::1"):

	    . {
		bind lo
	    }

     You can exclude some addresses by their IP or interface name (The following
     will  only listen on ::1 or whatever addresses have been assigned to the lo
     interface):

	    . {
		bind lo {
		    except 127.0.0.1
		}
	    }

BUGS
   AVOIDING LISTENER CONTENTION
     TL;DR, When adding the bind plugin to a server block, it must also be added
     to all other server blocks that listen on the same port.

     When more than one server block is configured to listen to a  common  port,
     those server blocks must either all use the bind plugin, or all use default
     binding  (no  bind  plugin).  Note that "port" here refers the TCP/UDP port
     that a server block is configured to serve (default 53) - not a network in-
     terface. For two server blocks listening on the same port, if one uses  the
     bind  plugin and the other does not, two separate listeners will be created
     that will contend for serving packets destined to the same address.   Doing
     so  will  result in unpredictable behavior (requests may be randomly served
     by either server). This happens because without the bind plugin,  a  server
     will  bind  to all interfaces, and this will collide with another server if
     it's using bind to listen to an address on the same port. For example,  the
     following creates two servers that both listen on 127.0.0.1:53, which would
     result in unpredictable behavior for queries in a.bad.example.com:

	    a.bad.example.com {
		bind 127.0.0.1
		forward . 1.2.3.4
	    }

	    bad.example.com {
		forward . 5.6.7.8
	    }

CoreDNS 			   March 2026			 COREDNS-BIND(7)

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