On Sat, 27 Nov 2004 01:13:31 +0800, Ian Dexter R. Marquez <[EMAIL PROTECTED]> wrote: > On Fri, 26 Nov 2004 22:59:08 +0800, ian sison (mailing list) > <[EMAIL PROTECTED]> wrote: > > You mean this? > > > > http://lartc.org/howto/lartc.rpdb.multiple-links.html > > > > :) > > > > Can this be done for *both* upstream and downstream routing? I mean: > we have two links, but most of the services we have (web, mail, etc) > use only one link so that when it bogs down -- which was fairly > recently -- we end up not having any service at all. It would be okay > if it was just a matter of switching over to the other link, but we're > constrained by our current IP address space allocation. > > My admittedly less-informed, semi-harebrained idea was to get > *another* IP block that is routable through both providers, who would > then both announce routes to us (BGP are for biggies, I think, those > with /19 or higher, but also possible with 'small fry' like us =D). > Hopefully, when one connection gets cut off, our routes are still up > on the other. > > If this has been done, how was it done using Linux routing? TIA.
For mail service, its as easy as setting up your MX records so that both links are used, and mail will get routed automatically to the link which is available. For DNS service, its as easy as setting up a dual homed host, and running the DNS service off it, and making the dual-homed IPs your primary and secondary DNS servers even if it's the same box. For other services, you can keep the TTL of the A records of your boxes low so that when a link goes down, a script can detect it and change the DNS entries automagically via a simple perl or sed command. Poor man's BGP :) Sometimes even more effective than BGP as it takes quite a while even for BGP rebroadcasts to take effect. The side effect to making your DNS TTL A records low is that DNS clients will hammer your DNS servers more often than they should, contributing for more bandwidth use. Ahhh trade offs.... -- Philippine Linux Users' Group (PLUG) Mailing List [EMAIL PROTECTED] (#PLUG @ irc.free.net.ph) Official Website: http://plug.linux.org.ph Searchable Archives: http://marc.free.net.ph . To leave, go to http://lists.q-linux.com/mailman/listinfo/plug . Are you a Linux newbie? To join the newbie list, go to http://lists.q-linux.com/mailman/listinfo/ph-linux-newbie
