Change ra0 to wlan0 in ubuntu 10.10

Question

I am trying to find a way to change the name of my Ralink interface to the usual wlan0.

The application I use is looking for this interface but since we changed our wifi adapter form Intel to ralink we miss the wlan0 because Ralink uses ra0 instead.

On all the forums and blogs I read that you need to change that in /etc/sysconfig/network-scripts/ifcfg-ra0. Ubuntu unfortunately does not have a /etc/sysconfig folder.

Answer 1

The device name is created by the kernel, but then you can add a rule to udev in order to rename the interface to the wanted device.

First make a backup of your configuration file

sudo cp /etc/udev/rules.d/70-persistent-net.rules /tmp/70-persistent-net.rules

You will be able to revert to the original state in case of something goes wrong by this command :

sudo cp /tmp/70-persistent-net.rules /etc/udev/rules.d/70-persistent-net.rules

Edit the file 70-persistent-net.rules in the udev rules directory :

sudo nano /etc/udev/rules.d/70-persistent-net.rules

Find the line corresponding to your persistent network device, this is something like that :

SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="xx:xx:xx:xx:xx:xx", ATTR{dev_id}=="0x0", ATTR{type}=="1", KERNEL=="ra*", NAME="ra0"

Change the name value to the wanted name so you will have a line like :

SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="xx:xx:xx:xx:xx:xx", ATTR{dev_id}=="0x0", ATTR{type}=="1", KERNEL=="ra*", NAME="wlan0"

Then reboot your computer and check that you have the right interface name.

Answer 2

The device name is set by the kernel and renamed to a human readable value by udev. udev will run the 75-persistent-net-generator.rules script in /lib/udev/rules/ which will generate the rules file 70-persistent-net.rules in /etc/udev/rules.d/

This the generator script will add new rules to the 70-persistent-net.rules file for every network adapter that is recognized by the kernel. When you replace a network card (ruled eth0) the old card will not be deleted form the rules, the new one is added though (eth1).

In my situation the network adapters are continuously changing. The hard disk is copied and placed in another computer with ecxactly the same setup, but the MAC addresses will be different every time. The position (PCIe) in the computer however will be the same every time. I did the following:

I turned off the rules generator by removing it from udev, but moved it for backup purposes:

sudo mv /lib/udev/rules.d/75-persistent-net-generator.rules /home/user/backup/

The rules will not be generated anymore. Then I edited the udev rules:

sudo nano /etc/udev/rules.d/70-persistent-net.rules

I removed the rules that were set by the generator and replaced them with:

ACTION=="add", SUBSYSTEM=="net", KERNELS=="0000:00:1c.0", NAME="eth0"
ACTION=="add", SUBSYSTEM=="net", KERNELS=="0000:00:1c.1", NAME="eth1"
ACTION=="add", SUBSYSTEM=="net", ATTR{type}==”1”, KERNEL=="ra*", NAME="wlan0"

Now my two network cards on the PCIe bus are named eth0 and eth1, and when I replace them, they will stay the same.

The last line will answer my question. The adapter passed by the kernel with a ra* name will be renamed to wlan0. In /etc/network/interfaces I can call "iface wlan0 inet dhcp"!

For me this is a working solution. I can copy this hard disk and put it in another machine with the same setup. AND IT WORKS! Now I can