Old goody, Gigabyte 6BXDS - dual PentiumII/III - and two NIC's. Installing Etch 4.0 - clean minimum - no appluications are selected, onlyy some tools.
First NIC is a Realtek 8169 gigabit ethernet card and the second is an Intel 100. Each of them use static IP address configuration.
After boot both of them obtain right IP address and working (seem to be) well but when using
#/etc/init.d/networking restart
I haver loose of them, only the loopback interface is working! How is it could be?

post
/etc/network/interfaces

/etc/network/interfaces

# 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
iface eth0 inet static
address 192.168.1.253
netmask 255.255.255.0
network 192.168.1.0
broadcast 192.168.1.255
gateway 192.168.1.254
# dns-* options are implemented by the resolvconf package, if installed
dns-nameservers 213.46.246.51 213.46.246.52
dns-search tovis-lab.hu

allow-hotplug eth1
iface eth1 inet static
address 172.31.28.53
netmask 255.255.255.0
network 172.31.28.0
broadcast 172.31.28.255



It does not seem to be wrong.
May be one thing, without "allow-hotplug eth1" does not up at all?!

What are you trying to do with eth1?

Nothing, for now - this box would be a firewall.
I need to reread ifconfig man page - instead of allow-hotplug - I simple need "auto eth0" and "auto eth1".

Run command as root

followed by

and see if the interfaces pulls the configuration and configures properly.

You could also see if you can ping the between the two nics by setting them on the same network and plugging into a switch to see if they can communicate.

try adding eth0 and eth1 after auto lo

so that it becomes

then it will try to bring all 3 interfaces up right after boot.