[H-GEN] Network Failover stuff

[Robert Brockway]

On Thu, 3 Jun 2004, Michael Anthon wrote:

> At this stage I'm really just looking for ideas on where to look and
> what sort of approach people would recommend and thought I would fire
> this off while I continue my research.

You can use Linux's advanced routing features to do load shared routes and
it is not much harder to do fail over.  There are recognised problems
getting this to work with Masquerade or DNAT on the same box though.

I got this advanced routing working but the Masquerade problem was a show
stopper for me.

I'm currently doing failover on a Cable and ADSL link by having the
default route change under certain conditions (interfaces going down,
etc).  I have a local squid box which has parents out both links and it
load shares web traffic out.  Specific host routes needed to be put in for
any box that needs to be connected through the interface which does not
normally carry the default route.

This was just a home project (yeah I ended up with 2 broadband
connections[1]) so didn't do it exactly as I would in a business setting.
In a busines setting I would use the advanced routing features and
masquerade on a seperate box.

The ADSL has dropped 2 or 3 times already and the failover has occured
seemlessly.  Failback when the ADSL link returns also works
perfectly.  My wife and I get emails (to local accounts) when either link
goes down or comes back up.

[1] I was originally migrating from Cable to ADSL.  When I did the sums it
turned out the savings for dropping the Cable were paltry (since it is
part of one of those bundles) so I have kept it, at least for now.

Rob

-- 
Robert Brockway B.Sc. email: robert at timetraveller.org, rbrockway at uqconnect.net
Linux counter project ID #16440 (http://counter.li.org)
"The earth is but one country and mankind its citizens" -Baha'u'llah