ipaddrsel man page on SmartOS

Man page or keyword search:  
man Server   16655 pages
apropos Keyword Search (all sections)
Output format
SmartOS logo
[printable version]


       ipaddrsel - configure IPv6 default address selection


       /usr/sbin/ipaddrsel -f file

       /usr/sbin/ipaddrsel -d

       Use  the ipaddrsel utility to configure the IPv6 default address selec‐
       tion policy table. The policy table is a longest-matching-prefix lookup
       table  that  is used for IPv6 source address selection and for destina‐
       tion address ordering when resolving names to AF_INET6 addresses. For a
       description  of	how the policy table is used for source address selec‐
       tion, see inet6(7P). For a description of how the policy table is  used
       for destination address ordering, see getaddrinfo(3SOCKET).

       The  unmodified policy table is valid for all typical IPv6 deployments.
       Modify the table only if a circumstance exists for  which  the  default
       behavior	 of  the  IPv6 source address selection or destination address
       ordering mechanism is unsatisfactory. See the  section for examples  of
       such  circumstances.  You  should  carefully  consider  your addressing
       strategy before you change the table from the provided default.

       When the ipaddrsel command is issued without any arguments, the address
       selection  policy currently in use is printed. The format of the output
       is compatible with the format of the configuration  file	 that  the  -f
       option accepts.

       Note -

	 If  the  usesrc subcommand to ifconfig(1M) is applied to a particular
	 physical interface, the selection policy specified  by	 usesrc	 over‐
	 rides	the  source address selection policies specified by ipaddrsel.
	 This is true for packets that are locally generated and for  applica‐
	 tions	 that	do   not   choose  a  non-zero	source	address	 using

   The Configuration File
       The configuration file that the -f option accepts  can  contain	either
       comment	lines or policy entries. Comment lines have a '#' character as
       the first non-blank character. and they are ignored  by	the  ipaddrsel
       utility. Policy entry lines have the following format:

	 prefix/prefix_length precedence label [# comment]

       The  prefix  must  be  an  IPv6	prefix	in  a  format  consistent with
       inet(3SOCKET). The prefix_length is an integer ranging from 0  to  128.
       The  IPv6  source  address  selection  and destination address ordering
       algorithms determine the precedence or label of an address by  doing  a
       longest-prefix-match lookup using the prefixes in this table, much like
       next-hop determination for a destination is done by  doing  a  longest-
       prefix-match lookup using an IP routing table.

       The precedence is a non-negative integer that represents how the desti‐
       nation address ordering mechanism will  sort  addresses	returned  from
       name lookups. In general, addresses with a higher precedence will be in
       front of addresses with a lower precedence. Other factors, such as des‐
       tinations  with	undesirable  source  addresses	can, however, override
       these precedence values.

       The label is a string of at most fifteen characters, not including  the
       NULL terminator. The label allows particular source address prefixes to
       be used with destination prefixes of the same label. Specifically,  for
       a  particular  destination  address,  the IPv6 source address selection
       algorithm prefers source addresses whose label is  equal	 that  of  the

       The label may be followed by an optional comment.

       The  file  must	contain a default policy entry, which is an entry with
       ::0/0 as its prefix and prefix_length. This is to ensure that all  pos‐
       sible addresses match a policy.

       The ippadrsel utility supports the following options:

       -f file
		  Replace  the	address selection policy table with the policy
		  specified in the file.

		  Revert the kernel's address selection policy table  back  to
		  the  default	table.	 Invoking  ipaddrsel  in this way only
		  changes the currently running	 kernel's  policy  table,  and
		  does	 not  alter  the  configuration	 file  /etc/inet/ipad‐
		  drsel.conf. To revert the configuration  file	 back  to  its
		  default  settings,  use ipaddrsel -d, then dump the contents
		  of the table to the configuration file  by  redirecting  the
		  output of ipaddrsel to /etc/inet/ipaddrsel.conf.

		    example# ipaddrsel -d
		    example# ipaddrsel > /etc/inet/ipaddrsel.conf

       Example 1 The Default Policy in /etc/inet/ipaddrsel.conf

       The  following  example	is  the	 default  policy  that	is  located in

	 # Prefix			     Precedence Label
	 ::1/128			     50 Loopback
	 ::/96				     20 IPv4_Compatible
	 ::ffff:		     10 IPv4
	 2002::/16			     30 6to4
	 ::/0				     40 Default

       Example 2 Assigning a Lower Precedence  to  Link-local  and  Site-local

       By  default,  the  destination address ordering rules sort addresses of
       smaller scope before those of larger scope.  For	 example,  if  a  name
       resolves	 to  a global and a site-local address, the site local address
       would be ordered before the global address. An administrator can	 over‐
       ride this ordering rule by assigning a lower precedence to addresses of
       smaller scope, as the following table demonstrates.

	 # Prefix			      Precedence Label
	 ::1/128			      50 Loopback
	 ::/0				      40 Default
	 2002::/16			      30 6to4
	 fec0::/10			      27 Site-Local
	 fe80::/10			      23 Link-Local
	 ::/96				      20 IPv4_Compatible
	 ::ffff:		      10 IPv4

       Example 3 Assigning Higher Precedence to IPv4 Destinations

       By default, IPv6 addresses are ordered in front of  IPv4	 addresses  in
       name  lookups.  ::ffff:  has  the  lowest  precedence	in the
       default table. In the following example, IPv4  addresses	 are  assigned
       higher precedence and are ordered in front of IPv6 destinations:

	 # Prefix			      Precedence Label
	 ::1/128			      50 Loopback
	 ::/0				      40 Default
	 2002::/16			      30 6to4
	 ::/96				      20 IPv4_Compatible
	 ::ffff:		      60 IPv4

       Example 4 Ensuring that a Particular Source Address is Used

       This example ensures that a particular source address is used only when
       communicating with destinations in a particular network.

       The following policy table assigns a label of 5 to a particular	source
       address	on  the local system, 2001:1111:1111::1. The table assigns the
       same label to a network, 2001:2222:2222::/48. The result of this policy
       is  that	 the  2001:1111:1111::1	 source address will only be used when
       communicating with destinations contained  in  the  2001:2222:2222::/48
       network.	 For  this example, this network is the ClientNet, which could
       represent a particular client's network.

	 # Prefix			       Precedence Label
	 ::1/128			       50 Loopback
	 2001:1111:1111::1/128		       40 ClientNet
	 2001:2222:2222::/48		       40 ClientNet
	 ::/0				       40 Default
	 2002::/16			       30 6to4
	 ::/96				       20 IPv4_Compatible
	 ::ffff:		       10 IPv4

       This example assumes that the local system has one physical  interface,
       and that all global prefixes are assigned to that physical interface.

       ipaddrsel returns the following exit values:

	     ipaddrsel successfully completed.

	     An error occurred. If a failure is encountered, the kernel's cur‐
	     rent policy table is unchanged.

				   The file that  contains  the	 IPv6  default
				   address selection policy to be installed at
				   boot time. This file is loaded  before  any
				   Internet services are started.

       See attributes(5) for descriptions of the following attributes:

       │Interface Stability │ Evolving	      │

       nscd(1M),   inet(3SOCKET),   getaddrinfo(3SOCKET),   ipaddrsel.conf(4),
       attributes(5), inet6(7P)

       The ipnodes cache kept by nscd(1M) contains addresses that are  ordered
       using  the  destination address ordering algorithm, which is one of the
       reasons why ipaddrsel is called before nscd in the  boot	 sequence.  If
       ipaddrsel is used to change the address selection policy after nscd has
       started, you should invalidate the nscd ipnodes	cache  invalidated  by
       invoking the following command:

	 example# /usr/sbin/nscd -i ipnodes

				  Feb 6, 2006			 IPADDRSEL(1M)

List of man pages available for SmartOS

Copyright (c) for man pages and the logo by the respective OS vendor.

For those who want to learn more, the polarhome community provides shell access and support.

[legal] [privacy] [GNU] [policy] [cookies] [netiquette] [sponsors] [FAQ]
Polarhome, production since 1999.
Member of Polarhome portal.
Based on Fawad Halim's script.
Vote for polarhome
Free Shell Accounts :: the biggest list on the net