Tuma Wang writes: > > Kyle McDonald writes: > > > Is it possible to configure multiple default routers with the > > > /etc/defaultrouter file? > > > > Yes. Just list multiple IP addresses, one per line. > > So what's the purpose (or semantics) of "multiple default routers"? To > my understanding, if a destination address doesn't get matched with > any "target network" or "target hosts" in the routing table, the > "default router" will be used. If there are more than one default > routers, which will be selected?
Either one -- they're specified as equivalent, so we can pick either route arbitrarily. What we actually do isn't documented and depends on software version. On "traditional" Solaris, we create IRE_CACHE entries for each destination IP address to which we send packets. This means that there's a one-time choice (when the IRE_CACHE entry is created) among the possible default routes, and then we stick with that, at least until the IRE_CACHE entry is aged away or otherwise deleted. The choice is made round-robin, and there's a static variable in the kernel that's used to select the next route in the list. Since the integration of Surya, which leaves IRE_CACHE usage for locally-initiated connections only and not forwarding, I'm not sure, but the point is that we pick essentially arbitrarily from the point of view of the user, and we can do that because the user has specified equivalent routes. For what it's worth, default routes shouldn't be considered "special." They're just a single case of a network route; one that happens to have a 0.0.0.0/0 destination. Other network routes can also be duplicated and longer term what we should be doing is hashing flows (source/dest IP and ports) among the available routes. -- James Carlson, Solaris Networking <[EMAIL PROTECTED]> Sun Microsystems / 35 Network Drive 71.232W Vox +1 781 442 2084 MS UBUR02-212 / Burlington MA 01803-2757 42.496N Fax +1 781 442 1677 _______________________________________________ networking-discuss mailing list [email protected]
