Re: Multihoming an end user - Debian

This is a discussion on Re: Multihoming an end user - Debian ; At 01:37 PM 9/24/05 -0400, dan@thecsl.org wrote: >Is it common for remote caches to ignore TTL and negative TTL? > >With a tiny ( >comfortably set DNS TTL and negative TTL to 60 seconds, even with >caching 3 levels deep, ...

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Thread: Re: Multihoming an end user

  1. Re: Multihoming an end user

    At 01:37 PM 9/24/05 -0400, dan@thecsl.org wrote:
    >Is it common for remote caches to ignore TTL and negative TTL?
    >
    >With a tiny (< 100 connections per day) user base, you can pretty
    >comfortably set DNS TTL and negative TTL to 60 seconds, even with
    >caching 3 levels deep, it will take 3 minutes for the right IP# to be used.


    Well setting a very small TTL is what u would have to do but it's not
    something that I would trust for any kind of "snap" change. As for the
    random BIND configs on the internet, there's no telling.

    >Also, if as was the case with the OP, ISP1# cuts service off explicitly
    >and deliberately for political reasons, they are also likely to suddenly
    >stop routing.
    >How would such a cut-off effect the whole
    >ARIN/ASN/BGP/magic-beyond-my-humble-understanding thing?


    In that case everything would fail over to ISP2 since there is a valid world
    known route to u through that ISP. Now theoretically if u got ur block from
    ISP1 they could take back their IP block and kill ur ASN routability.
    Getting an independent block is the way to keep that from happening. No
    matter what either ISP does u still control the routing. Of course u need
    some ISP to push that route out to the world.


    Another question for the original poster: How is it that u have two DSL
    lines from two providers? Usually one provider controls the local loop, and
    in that case both DSL lines would be going out over the *same* CO, DSLAM,
    ATM, etc until it branched out to the ISP's network.






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    "...ne cede malis"

    00000100


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  2. Re: Multihoming an end user


    >Another question for the original poster: How is it that u have two DSL
    >lines from two providers? Usually one provider controls the local loop, and
    >in that case both DSL lines would be going out over the *same* CO, DSLAM,
    >ATM, etc until it branched out to the ISP's network.
    >
    >


    ISP1 is a 3Mbps wireless connection to a local ISP. They in turn have a
    bonded T1 to AT&T. As far as I know, this is their only connection.
    (not speaking BGP). ISP2 is a 1.5 Mbps DSL through the local phone
    company, SBC.

    Thinking bigger scope, we have a T1 connection to our parent company
    used for VoIP applications. They also have a T1 or greater connection
    to the internet. If we move to a T1 locally, we might be able to
    convince them to split a new /24 and route BGP over these two links.
    This is however, beyond my call.


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