Tuesday, 3 June 2003 at 9:05pm, Martin wrote: [snip]
I disagree. An end host with a single interface, as in this situation, has no business trying to make load-balancing decisions that would be best made by the router owning the multiple interfaces with the information about the state of those interfaces as well as the knowledge about traffic on them from other end hosts. Moreover, router redundancy is handled by routers, not hosts, as it is very undesirable that hosts actually have to make decisions about what router to attempt to reach. VRRP, for example, makes it simple to hosts not to need to worry about what router to contact.
Agreed, but VRRP/HSRP was not subject here ... there are still some routers which don't support that, subject was whether it makes sense :) and to me it does if you don't have any other options. Not that I would ever do that but I've seen folks doing it this way for redundancy or just for heck of it they could.
This is getting intriguing.... Assuming it makes sense, what I'd like to understand then, on a system with a single ethernet interface and a route table with two default routes, how is the kernel going to know which of the two gateways to use? Suppose one of the gateway hosts has its far side interface down for some reason--how will the end host learn that gateway router isn't really usable? I suppose that the router will return an ICMP "Host not reachable" or "Network not reachable", but I don't see how that will help. You also mentioned load-balancing earlier. I'm aware of load balancing a web site with multiple servers using DNS round robin or with NAT, and there are others, such as supersparrow, which uses BGP, IIRC. But how does one do load balancing from a single host with a single network interface and using only a static route table? I'm not trying to be stubborn about this--I truly would like to know, and if you've seen people do it, please describe it. Thanks. Jim