I am trying to set up failover default routes. The situation is three
OpenBSD machines, client, rtr0 and rtr1. Client has two interfaces, one
with a crossover link to rtr0 and one to rtr1. I would like the default
route for client to be rtr0 unless rtr0 has failed in some way
(unreachable, etc). As far as I know, I can not use carp to give a
single default route ip carp'd between rtr0 and rtr1 because they are
not on a shared network. I know this has been discussed before and have
read some archived posts (including the recent "inet failover solution"
thread) but still have questions. I have read about the following
options but would like some guidance/advice (and of course any pointers
to previous docs/posts):
1) ifstated with ping and if.up tests and executing route commands
The idea here would be ifstated would trigger commands something like:
route delete default rtr0.ip; route add default rtr1.ip

2) ifstated executing pf table change commands
Same sort of tests, but instead of issuing route commands, change a pf
table that is being used as a "route-to". I am not sure exactly what
this would look like yet. I am not sure what this would look like yet, I
am still reading more on route-to.

Downsides to ifstated approach is that I would like to use ifstated to
also control a different set of interfaces from client, so this may
create a complex many-state ifstated.conf.

3) new multipath routing, but somehow disable one route
This one confuses me a bit. I read the presentation about the new
multipath routing and some associated docs and it seems that multipath
routing can only be used for balancing across routes based on source. I
really want to have a failover set up, NOT load balancing so I don't
think this would work.

4) ospf, bgp
I am aware of these routing daemons but really don't know too much about
them. I read some docs and it seemed overly complex for setting up just
a simple failover default route on internal machines.

Thanks in advance,
Chris

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