.. SPDX-License-Identifier: GPL-2.0
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===========
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IP-Aliasing
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===========
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IP-aliases are an obsolete way to manage multiple IP-addresses/masks
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per interface. Newer tools such as iproute2 support multiple
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address/prefixes per interface, but aliases are still supported
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for backwards compatibility.
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An alias is formed by adding a colon and a string when running ifconfig.
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This string is usually numeric, but this is not a must.
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Alias creation
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==============
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Alias creation is done by 'magic' interface naming: eg. to create a
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200.1.1.1 alias for eth0 ...
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::
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# ifconfig eth0:0 200.1.1.1 etc,etc....
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~~ -> request alias #0 creation (if not yet exists) for eth0
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The corresponding route is also set up by this command. Please note:
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The route always points to the base interface.
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Alias deletion
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==============
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The alias is removed by shutting the alias down::
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# ifconfig eth0:0 down
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~~~~~~~~~~ -> will delete alias
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Alias (re-)configuring
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======================
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Aliases are not real devices, but programs should be able to configure
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and refer to them as usual (ifconfig, route, etc).
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Relationship with main device
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=============================
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If the base device is shut down the added aliases will be deleted too.
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