| Tobin C. Harding | 735dadf | 2018-07-18 13:27:35 +1000 | [diff] [blame] | 1 | .. SPDX-License-Identifier: GPL-2.0 |
| 2 | |
| 3 | =========== |
| 4 | IP-Aliasing |
| 5 | =========== |
| 6 | |
| 7 | IP-aliases are an obsolete way to manage multiple IP-addresses/masks |
| 8 | per interface. Newer tools such as iproute2 support multiple |
| 9 | address/prefixes per interface, but aliases are still supported |
| 10 | for backwards compatibility. |
| 11 | |
| 12 | An alias is formed by adding a colon and a string when running ifconfig. |
| 13 | This string is usually numeric, but this is not a must. |
| 14 | |
| 15 | |
| 16 | Alias creation |
| 17 | ============== |
| 18 | |
| 19 | Alias creation is done by 'magic' interface naming: eg. to create a |
| 20 | 200.1.1.1 alias for eth0 ... |
| 21 | :: |
| 22 | |
| 23 | # ifconfig eth0:0 200.1.1.1 etc,etc.... |
| 24 | ~~ -> request alias #0 creation (if not yet exists) for eth0 |
| 25 | |
| 26 | The corresponding route is also set up by this command. Please note: |
| 27 | The route always points to the base interface. |
| 28 | |
| 29 | |
| 30 | Alias deletion |
| 31 | ============== |
| 32 | |
| 33 | The alias is removed by shutting the alias down:: |
| 34 | |
| 35 | # ifconfig eth0:0 down |
| 36 | ~~~~~~~~~~ -> will delete alias |
| 37 | |
| 38 | |
| 39 | Alias (re-)configuring |
| 40 | ====================== |
| 41 | |
| 42 | Aliases are not real devices, but programs should be able to configure |
| 43 | and refer to them as usual (ifconfig, route, etc). |
| 44 | |
| 45 | |
| 46 | Relationship with main device |
| 47 | ============================= |
| 48 | |
| 49 | If the base device is shut down the added aliases will be deleted too. |