Debian: Activate network connection on powerup

Question

Is there a way to force the network connection to be active before logging in?

I have a debian (squeeze 6.0.5 64 bit) workstation, and I would like the network connection to be activated directly on powerup. Right now, the network connection (wired LAN, DHCP) activates only when I log in.

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Additional info:

File: /etc/network/intefaces

# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).

# The loopback network interface
auto lo
iface lo inet loopback

# The primary network interface
allow-hotplug eth0
#NetworkManager#iface eth0 inet dhcp 

Answer 1

The issue is you have a userspace program which manages your wired connection, called NetworkManager. Since this program doesn't start until login, your ethernet is not available until it starts up and configures it.

If you're willing to forgo the ease of reconfiguring with the GUI, try this:

1. Back up your interface file: sudo cp /etc/network/interfaces /etc/network/interfaces.bak
2. Edit your interface file: sudo nano /etc/network/interfaces
   1. Tell it to bring up eth0 automatically by changing the auto lo to auto lo eth0
   2. Remove the #NetworkManager# part from the last line, so that it reads iface eth0 inet dhcp
   3. Ctrl+O to save, Ctrl+X to exit.
3. Reboot your computer.

If that doesn't fix it, just restore the backup to revert the changes and continue troubleshooting: sudo cp /etc/network/interfaces.bak /etc/network/interfaces

Following these changes, you will need to manage your network interface manually. You should read up on ifconfig and the /etc/network/interfaces file. It would probably also be good to read up on NetworkManager.