Re: Multiple Internet addresses

Mark Fedor (
Thu, 17 Sep 87 11:39:58 EDT

>Date: Wed, 16 Sep 87 20:45:08 EDT
>From: Mike Muuss <>
>Subject: Re: Multiple Internet addresses
>The strategy that we have used at BRL (implemented by J. Pistritto)
>for many years now is to run a simple program on each local net host
>(called "router") that is given a prioritized list of "default routes".
>The highest priority route that meets certain maximum roundtrip times (<
>5 sec) and maximum packet loss rates (50%) is selected. When the
>highest priority route is not selected, all higher priority ones are
>PINGed at a slow rates (once/minute). When a higher priority path
>becomes acceptable again, the default route is switched back to it.
>No PINGs leave the local network, and the ping rate is very low.
>4.3 BSD does the rest, handling redirects, etc., that the gateway issues,
>and reconsulting the routing tables when a TCP connection is "halfway"
>timed out.
>We have found this strategy to work very successfully.
> -Mike


        This sounds interesting, but your letter left me with a question
        on "router". Since 4.3BSD does not time out/delete routes learned via
        a redirect from the kernel, does the "router" program delete a
        redirect-learned route if the gateway for that route goes away?

        Hope this is clear enough...


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