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Re: Adding a 2nd NIC to create a DMZ

On Thu, 14 Jun 2001, Michael Boyd wrote:

> My firewall machine currently has just one NIC with the driver installed
> when I originally installed Debian using dbootstrap.  I don't understand
> what that means about how the driver is installed on the system.
> Perhaps you could enlighten me?

If you compiled the kernel which runs on your system, then you had to
choose which device drivers include in the kernel proper, which to compile
as modules and which to leave out completely. If the driver for your
NIC was compiled in the kernel proper, you don't have to do anything, the
kernel will recognise the NIC upon booting and assign a device name to it.
If the driver for your card was compiled as a kernel module, you will have
to load it in order for the kernel to initialise and be able to use your
NIC. You do it with the command

modprobe appropriate_module_for_your_NIC

following which the kernel will recognise your NIC and assign a device
name to it.

The modules listed in the file /etc/modules are loaded by default in a
debian system, early during the boot process, and in the same order in
which they are listed. Therefore, in order to be sure they are loaded and
that this is done in a well defined order so that you know which one will
be, say, eth0 and which one eth1, you have to put the appropriate module
names in the /etc/modules file, in an order which you choose. The device
names for ethernet cards are assigned as ethX, with X a number starting
from zero and increasing. The NICs whose drivers were compiled into the
kernel (if any) will get the lowest number(s); among them, the order
depends on what their driver is and on the slot they are inserted in, but
it is always the same if you do not change NICs or slots. Then, NICs whose
drivers are loaded as modules are given device numbers in the same order
in which their modules are inserted in the kernel; if more than one NIC is
driven by the same module, as above, the order depends on the slots they
are in, and is well defined and repeatable.

> How do I install the driver for the second card
> and ensure that the machine knows the card is there?

As above, modprobe the appropriate kernel module, assuming it was compiled
in the running kernel. Otherwise, you will have to compile a fresh kernel,
making sure you configure it to compile all the device drivers you need,
either in the kernel itself or as modules.

Hope this helps, bye


Giacomo Mulas <gmulas@ca.astro.it, giacomo.mulas@tin.it>

Str. 54, Loc. Poggio dei Pini * 09012 Capoterra (CA)

Tel.: +39 070 71180 216     Fax : +39 070 71180 222

"When the storms are raging around you, stay right where you are"
                         (Freddy Mercury)

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