How to config USB ethernet to have a static IP?

Question

I have a USB device that works as a USB RNDIS ethernet device.

This device does not have DHCP capability so the host computer needs to allocate IP address for itself.

I tried to add to the /etc/network/interfaces

auto usb0
iface usb0 inet static
    address 192.168.7.15
    netmask 255.255.255.0
    network 192.168.7.0

Then I run into the problem similar to this one: when the device is not connected then usb0 will not show, and network-manager would fail at boot.

Is there a way to work around this?

Solution

If you need to plug/unplug very frequently, a HWaddr should bind to the device like this 12:a5:cf:42:92:fd. For my case, I'm using g_ether.ko on an embeded linux system, run "insmod g_ether.ko host_addr=12:a5:cf:42:92:fd dev_addr=5e:bc:ca:27:92:b1". Then on the linux host (Ubuntu 12.04 LTS for my case), edit the file "/etc/NetworkManager/system-connections/Wired connection 2", and input something like

####################################
[802-3-ethernet]

duplex=full
mac-address=12:a5:cf:42:92:fd

[connection]

id=Wired connection 2
uuid=2862a666-c2e6-4a3a-8e0c-8705d93c92da
type=802-3-ethernet
timestamp=1501735507

[ipv6]

method=auto

[ipv4]

method=manual

addresses1=192.168.42.21;24;192.168.42.1;
###############################################

Last, save the file, and plug/replug the usb cable.

Comments

[Pilot6]

No devices have "DHCP capability". It is done by the OS. If you setup interface this way, NM will not manage it anyway. It is totally unclear what are you asking.

[user3528438]

@Pilot6 I mean, when the device is connected to the host, the device can not allocate an IP address for the host.

[user3528438]

Because this is a peer-to-peer direct connection and there is not DHCP server, so the two sides needs to allocate/configure IP address for themselves. I'm trying to hard code an IP address in /etc/network/interfaces which caused problems.

[Ijaz Ahmad]

Ok , remove network manager and then hard code it on both sides , they should be on the same subnet

[user3528438]

Then how would other adapters work if network manager is disabled?

[user3528438]

Well, I know this approach but everytime the device is connected, it creates a new connection, and I need to manually change the settings everytime. Since I need to plug/unplug and boot/reboot the device very frequently, I'm trying to figure out a way to make the settings persistent.

[Ijaz Ahmad]

I am using wireless adapter without NM. NM had many problems so i removed it

[dobey]

That sounds like a bug in network-manager then, and you should report it.

[user3528438]

You are right. The reason the host side can not remember the IP settings is the device side uses a different mac address each time the module is mounted. So the solution is to use module parameters to set a fixed mac, preferably a device unique value on boot and when the module is mounted.