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