On 01/02/12 21:06, Les Mikesell wrote:
Hmm...
I just tried this and besides needing ip route "add" default
It does not seem to work when I unplug the cable on my primary link.
Well, I should disclose that is an experiment, and I may not have explained the config fully - see the pages I referenced for more authoritative information. I did think I had it working but I am less sure now, and caching looks like it may be a problem.
I should emphasise that the main question I have here is: is RHEL's scheme for configuring routing flexible enough to accommodate such configurations?
And if it isn't, is there anything I should bear in mind when hacking a script to do this sort of thing, in order to avoid breaking my system or generally fighting against the system's assumptions?
I don't think CentOS is smart enough to automatically drop routes associated with a NIC that is down like a Cisco would. If you put routes in /etc/sysconfig/network-scripts/routes-eth? to match the device names, the ifup and ifdown scripts will add/remove routes when you manually run time to enable/disable a particular NIC,
Right; and then one NIC's state controls the routing configuration for both. I can't see an easy way around that.
but that doesn't get you automatic failover. And with ethernet type devices it is pretty rare for the link to go away at the same time the packets stop getting through anyway.
Just to clarify, by "that" do you mean custom "routes in [..]/routes-eth?" or the nexthop configuration I mentioned? It'd guess the former, but I'm more interested in the latter.
Based on some tests I suspect it works initially, then if things change, the routing cache will keep the old non-working config until someone flushes it. Note, I'm not sure about this either (due to the general fog of fatigue), and I'm thinking I should try a an entirely different approach.
Thanks,
N