change IP address (static/DHCP)

[niklasmolin]

Hi.

I'm running an image (Yocto) on a SabreSD board and wonder how I change from DCHP client mode to static mode, when it comes to setting the network port?

How do I a turn on/off DHCP from the command line?

Also, how do I change the MAC address?

Thanks,

Niklas

[AnsonHuang]

To disable DHCP, please remove it(ip=dhcp) in uboot command line;

To use a static IP, you can use ifconfig command such as:

ifconfig eth0 10.192.242.117

To change MAC address, you can use below command in commandline:

fec.macaddr=0x00,0x10,0x20,0x30,0x40,0x88

[niklasmolin]

Hi Yongcai.

This means that I can only run the image with either DCHP on or off.

In our case we want to be able to change it dynamically, when the Linux image is running.

I found in /etc/networking/interfaces that I think I should be able to change this setting.

[b36401]

As for MAC address it can be permanently changed by burning e-fuse.
Alternatively you can add the command like this

ifconfig eth0 hw ether 00:04:9f:00:e9:bb

into init script of the system to overwrite the value.

[b36401]

You can simply add "ifconfig" command with exact IP address into system init script.
And when the system is running you can use "ifconfig" command as well.

[claymontgomery]

The better way to configure eth0 for a static IP address, rather than dhcp, is like this in the  /etc/network/interfaces  file:

# Wired or wireless interfaces
auto eth0
#iface eth0 inet dhcp
iface eth0 inet static
        address 192.168.0.100
        netmask 255.255.255.0
        gateway 192.168.0.1

There is a good tutorial here:

   https://www.howtoforge.com/tutorial/howto-set-a-static-ip-on-ubuntu/ 

Regards, Clay

[AnsonHuang]

as far as I know, if you want to enable DHCP, you can ifconfig eht0 down, then ifconfig eth0 up, udhcpc eth0.....not sure whether it helps.