Ethernet Bonding
NOTE: I believe this only works if both interfaces are on the same network. These are quick notes only and does not comprise a full article yet but...
This article is intended to show how to use Ethernet bonding as a 'high availablity' (fail-over) solution.
Setup Bonding Ethernet on Debian and Ubuntu with a 2.6 kernel
To use Bonding Ethernet for High-Available on Debian (Etch, Lenny, Squeeze) and Ubuntu (Hardy 8.04 and up) you need to ensure you have the 'ifenslave' package installed. For example:
apt-get install ifenslave-2.6
make sure the real NICs kernel modules are loaded automatically.
edit /etc/network/interfaces to look like this:
iface bond0 inet static address 10.31.1.5 netmask 255.255.255.0 network 10.31.1.0 gateway 10.31.1.254 up /sbin/ifenslave bond0 eth0 up /sbin/ifenslave bond0 eth1
comment or borrow the lines referring to your real NICs in the same file. Then add the following lines to your /etc/modprobe.d/arch/i386 file:
alias bond0 bonding options bonding mode=1 miimon=100 downdelay=200 updelay=200
More to come as this article becomes an actual article...