How to secure Ethernet environment on L4 Linux ?

Hello, l4hackers

After I succeeded putting other package in ramdisk, I'm trying to take
Ethernet on L4 Linux.

When I built L4 Linux , I've configured '[*]Network support ' and
'[*]Network device driver support'.
I've copied 'etc' folder from other file system and put it in ramdisk.
And I've put somethings about Network in ramdisk.

Manually I've mounted '/proc' and '/sys' and tried to run command 'if -a'.
But I've failed secure Ethernet environment on L4 Linux.
To put it concretely, I was not able to run command 'ifup -a' successfully.

Please , Help me
Even if you tell a bit hints to me, I thank you.