Multihomed Routing (was Re: Multiple Interfaces)

From: Michael W. Oliver (michael_at_gargantuan.com)
Date: 07/31/03

  • Next message: Andrea Venturoli: "freevrrp" 
    To: Barney Wolff <barney@databus.com>, Bob <bob@starblanket.ca>
Date: Thu, 31 Jul 2003 14:36:36 -0400

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    +--- On Thursday, July 31, 2003 14:13,
    | Barney Wolff proclaimed:
    |
    | On Thu, Jul 31, 2003 at 11:07:18AM -0600, Bob wrote:
    | > All you are missing is the fact FreeBSD cannot handle
    | > two NICs the same subnet. OpenBSD does, NetBSD does and Linux does.
    |
    | Wrong. As already stated, make the netmask on the second one /32.
    |
    | Re freevrrpd, so far as I know it's intended for the case of two machines
    | where one backs up the other, not two interfaces on one machine taking
    | over for each other.

    I may be wrong here, but the problem lies in having duplicate routes in the
    routing table, which is what would happen if two interfaces were in the
    same network and had the same mask (/26 for example). This is solved by
    having a different mask for the second interface (much like using the /32
    for VRRPd), but it is only a band-aid.

    I am no programmer, so forgive my ignorance in that respect, but why can't a
    metric be used to differentiate routes to the same destination network
    within the routing table? I happened to be googling and found:

    http://daily.daemonnews.org/view_story.php3?story_id=3878

    which describes exactly what I am talking about. Is there any reason why
    this shouldn't be implemented by default in the OS? Personally, I would
    very much like the ability of Zebra to feed the kernel the same route to
    multiple destinations, differentiating those routes by metric value.

    Comments?

    - --
    +-------------------------------------+------------------------------+
    | Michael W. Oliver, CCNP | "The tree of liberty must be |
    | IPv6 & FreeBSD mark | refreshed from time to time |
    | michael@gargantuan.com | with the blood of patriots |
    | http://michael.gargantuan.com/ | and tyrants." |
    | ASpath-tree, Looking Glass, etc. | - President Thomas Jefferson |
    | +------------------------------+
    | gpg key - http://michael.gargantuan.com/gnupg/pubkey.asc |
    +--------------------------------------------------------------------+

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  • Next message: Andrea Venturoli: "freevrrp"

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