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ipnodes(4)			 File Formats			    ipnodes(4)

       ipnodes - local database	associating names of nodes with	IP addresses


       The ipnodes file	is a local database that associates the	names of nodes
       with their Internet Protocol (IP) addresses. IP addresses can be	either
       an IPv4 or an IPv6 address. The ipnodes file can	be used	in conjunction
       with, or	 instead of, other ipnodes databases,	including  the	Domain
       Name  System  (DNS),  the  NIS ipnodes map, and the NIS+	ipnodes	table.
       Programs	use library interfaces to access information  in  the  ipnodes

       The  ipnodes  file has one entry	for each IP address of each node. If a
       node has	more than one IP address, it will have one entry for each,  on
       consecutive lines.  The format of each line is:

       IP-address official-node-name nicknames...

       Items  are separated by any number of <SPACE> and/or <TAB>  characters.
       The  first item on a line is the	node's IP address. The second entry is
       the   node's official name. Subsequent entries on the same line are al-
       ternative names for the same machine, or	"nicknames." Nicknames are op-

       For a node with more than one IP	address, consecutive entries for these
       addresses may contain the same or differing nicknames.  Different nick-
       names are useful	for assigning distinct names to	different addresses.

       A call to getipnodebyname(3SOCKET) returns a hostent structure contain-
	the  union of all addresses and	nicknames from each line containing  a
       matching	official name or nickname.

       A `#' indicates the beginning of	a comment; characters up to the	end of
       the line	are not	interpreted by routines	that search the	file.

       Network addresses are written in	one of two ways:

	  o  The conventional "decimal dot" notation and interpreted using the
	     inet_addr	routine	 from  the  Internet address  manipulation li-
	     brary, inet(3SOCKET).

	  o  The IP Version 6 protocol [IPV6], defined in RFC 1884 and	inter-
	     preted  using  the	 inet_pton() routine from the Internet address
	     manipulation library. See inet(3SOCKET).

       These interfaces	supports node names as defined	in  Internet  RFC  952
       which states:

       A  "name" (Net, Host, Gateway, or Domain	name)  is  a text string up to
       24 characters drawn from	the alphabet (A-Z), digits (0-9),  minus  sign
       (-),  and   period  (.).	  Note that periods are	only allowed when they
       serve to	delimit	components of "domain style  names".   (See  RFC  921,
       "Domain Name System  Implementation Schedule," for background).
	No  blank  or space characters are permitted  as part of  a name.   No
       distinction is made between upper and lower case.  The first  character
       must be an alpha	character. The last character must not be a minus sign
       or period.

       Although	the interface accepts node names longer	than 24	characters for
       the  node  portion  (exclusive of the domain component),	choosing names
       for  nodes that adhere to the 24	character restriction will insure max-
       imum interoperability on	the Internet.

       A  node	which  serves  as a GATEWAY should have	"-GATEWAY" or "-GW" as
       part of its name.  Nodes	which do not serve as Internet gateways	should
       not  use	 "-GATEWAY" and	"-GW"  as part	of  their  names.  A node that
       is a TAC	should have "-TAC" as the last part of its node	name, if it is
       a DoD node.  Single character names or nicknames	are not	allowed.

       RFC  952	has been modified by RFC 1123 to relax the  restriction	on the
       first character being a digit.

       Example 1: A Typical Line from the ipnodes File

       The following is	a typical line from the	ipnodes	file:

	2::56:a00:20ff:fe7b:b667	foo		# John Smith

       in.named(1M),	 getipnodebyname(3SOCKET),     inet(3SOCKET),	  nss-
       witch.conf(4), resolv.conf(4), hosts(4)

       Braden,	B., editor, RFC	1123, Requirements for Internet	Hosts -	Appli-
       cation and Support, Network Working Group, October, 1989.

       Harrenstien, K.,	Stahl, M., and Feinler,	E., RFC	952, DOD INTERNET HOST
       TABLE SPECIFICATION, Network Working Group, October 1985.

       Hinden, R., and Deering,	S., editors, RFC 1884, IP Version 6 Addressing
       Architecture, Network Working Group, December, 1995.

       Postel, Jon, RFC	921, Domain Name System	  Implementation  Schedule  --
       Revised,	Network	Working	Group, October 1984.

       IPv4 addresses can be defined in	the ipnodes file or in the hosts file.
       See hosts(4).  The ipnodes file will be	searched  for  IPv4  addresses
       when  using  the	 getipnodebyname(3SOCKET) API. If no matching IPv4 ad-
       dresses are found in the	ipnodes	file, then  the	 hosts	file  will  be
       searched.   To	prevent	  delays   in  name  resolution	 and  to  keep
       /etc/inet/ipnodes and /etc/inet/hosts synchronized, IPv4	addresses  de-
       fined in	the hosts file should be copied	to the ipnodes file.

SunOS 5.9			  25 Oct 1999			    ipnodes(4)


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