Failover/Loadbalancing with dynamic gateways

jiggiday · Feb 19, 2009, 6:26 PM

I have read conflicting answers to this question in many of the threads here, so I am trying to clarify what the expected behaviour is.

I have a 3 wan failover pool. All of my WAN's use DHCP and the gateways (all 3) can potentially change.

I have all three wan interfaces in the pool, and when configuring them I select the corresponding gateway (ie, WAN's Gateway, OPT1's Gateway, OPT2's Gateway) rather than the gateway's IP address. I believe that the rc.newwanip script is supposed to update the slbd.conf file with new IP address and gatway information if the WAN interface ip changes. In my testing, I have found that if I change the ip and gateway going to one of the WANs, the Failover pool continues to ping the old gateway address and will mark the service as down, rather than detecting that the gateway has changed and trying to ping the new gateway. Should the gateways used in the Failover/Load Balancer service update with new DHCP assigned network configuration info, or not?

Thanks,
Jason

jiggiday · Feb 20, 2009, 7:38 PM

All I'm really looking for is confirmation, something like, "yes, the gateways are supposed to update, there is something wrong with your config" or "No, once the gateways are set for the loadbalancer, they are static."

jasonlitka · Feb 24, 2009, 4:52 PM

I don't have an answer to your question, but a workaround is to ping something with a fixed IP that's close rather than your gateway. Try 4.2.2.1 (an anycast DNS server).

Fitopy · Feb 25, 2009, 4:53 PM

jasonlitka…that would necesarily need to make a policy route for that static IP address just to force that pings go trough that interface

ktims · Feb 25, 2009, 8:12 PM

@Fitopy:

jasonlitka…that would necesarily need to make a policy route for that static IP address just to force that pings go trough that interface

That happens automagically, as long as the interface comes up during bootup.

jiggiday · Feb 26, 2009, 1:35 AM

Thanks for your advice jasonlitka.

For reference, the answer is that the gateway addresses do not update with new dhcp information. I think I will just use carefully selected ip addresses to ping.