[ale] Does anybody have experience with a load-balancing/failover distro?

[Michael Trausch]

You should be able to do this with any distribution.  You need only to have:
  * Setup eth0 with the first connection
  * Setup eth1 with the second connection
  * Setup eth2 as the LAN's RFC1918 space and have it answer DHCP and
do all the "normal" things.

Now, write your iptables rules for Internet-through-eth0 and create a
modified copy of that for Internet-through-eth1.

Now, keep a file, say, /var/run/active-connection, that has the name
of the currently active connection in it (either eth0 or eth1).

Have a cron job that, once per minute, pings the gateway address for
whatever interface is listed in /var/run/active-connection.  If it is
down, then reconfigure the routing table and IP masquerading for the
second connection, mark the change in /var/run/active-connection, and
go from there.

I'd leverage /etc/network/interfaces on Debian and derivatives.  All
you need to do is hook into that so that "ifdown eth0" and "ifup eth1"
are all you need, and you should probably have it setup so that you
cannot "ifup" on both interfaces at the same time, unless you have a
static IP address from both ISPs.

I haven't gotten around to it yet, but what I would like to do is
create a little embedded doohickey that will do just this, with three
Ethernet ports (two in, one out) and a USB port for configuration
(serial ports don't exist on modern systems anymore, so might as well
just use a USB port and make it act like a serial port...).  And the
default configuration of the device would just be for a standard
network with two standard DHCP-providing ISPs, such that a "completely
standard" setup would Just Work.  Me being me, I'll probably (when I
get to it) even have the thing create an IPv6 tunnel and advertise
IPv6 connectivity, because I just can't see the point of not doing so.
 :-)

   --- Mike

On Tue, Sep 28, 2010 at 12:08 PM, david w. millians <millia at panix.com> wrote:
>
> I've got a district that is getting a second internet connection for
> redundancy purposes. They would therefore love to have a load balancing
> and failover appliance. Obviously, there are some vendors that have
> products to sell them, and also obviously, they cost money that they
> don't have.
>
> A fair number of districts have used "untangle" before, but it appears
> that they charge for the lb/f capability; it's not included in the free
> download. It may be cheaper for them since they don't need firewall,
> filtering, etc., but free is preferred, since even the box to do this is
> a factor...
>
> So, do you know of/have you used any linux distros that do this well and
> easily? I'm going to go to distrowatch now, but I just want to know of
> good experiences.
>
> Thanks,
> David
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