ifscheme-mapping (8)

ifscheme [-v] [[-s] newscheme]

mapping <interface> script ifscheme-mapping

ifscheme allows you to change network configuraton schemes or query the current scheme. It integrates with the ifup(8) command and interfaces(5). For example, you might use this program to configure a "home" scheme and a "work" scheme for a network device on a laptop. When you move between home and work, a simple command can reconfigure your networking.

If you run the program with no parameters, it will tell what the current network scheme is.

The ifscheme-mapping utility is used to tell the ifup and ifdown utilities about the current scheme.

-v

--verbose

Run in verbose mode. This is passed in to the ifup and ifdown programs as well.

-l

--list

list all schemes available/defined in /etc/network/interfaces.

newscheme

-s newscheme

--scheme newscheme

Change to a new network configuration scheme. When the scheme is changed, network interfaces that were using the old scheme will be taken down and brought back up to use the new configuration scheme. -s or --scheme are mandatory if newscheme begins with a -.

To make the program do anything useful when a scheme is selected, you must edit /etc/network/interfaces to add a mapping for the interface (or interfaces) that can be controlled on a per-scheme basis. Suppose you want to control eth0 in this way. You might have an existing eth0 configuraton in there, such as:

  auto eth0

  iface eth0 inet static
  	address 192.168.1.5
  	netmask 255.255.255.0
  	gateway 192.168.1.1

To change this so you can chose between static routing and dhcp, replace it with the following (it helps to ifdown the interface first).

  auto eth0

  mapping eth0
  	script ifscheme-mapping

  iface eth0-home inet static
  	address 192.168.1.5
  	netmask 255.255.255.0
  	gateway 192.168.1.1

  iface eth0-work inet dhcp

Now if you run "ifscheme home" and ifup the interface, you'll get the eth0-home configuration stanza. If you run "ifscheme work", it will be changed to the eth0-work stanza. You can add additional stanzas as desired, but the label must always be of the form <hardware interface>-<scheme name>.

If you have a second interface (perhaps a wireless network card on eth1), you can duplicate the above for that interface, changing the eth0 and the configuration details as appropriate, but remember to add an iface stanza for every scheme name for the second interface.

/etc/network/interfaces

the interfaces definition file

/etc/network/run/scheme

the current scheme

/etc/network/run/ifstate

a record of the current state of the interfaces, managed by ifup and ifdown

All schemed interfaces will have the same scheme.

Any schemed interface which does not have an entry for the current scheme and is not configured when the scheme is changed will not be successfully configured when it is brought up.

interfaces(5) ifup(8) ifdown(8)

Redistribution is subject to the GNU public license.

Joey Hess <[email protected]>, Peter Wilson <[email protected]>