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1 webserver, 2 ISPs

SeñorAmorSeñorAmor !!!Registered User regular
edited June 2008 in Help / Advice Forum
Here at the office, we have our own webserver and host a few of our sites. We also have internet connections from 3 different ISPs. What I'd like to do is set up my nameservers and DNS entries for my sites so they will still work on an alternate IP if the primary one fails. How do I set this up so that mysite.com resolves to 1.2.3.4 first and 5.6.7.8 if the first IP is not reachable?

Thanks in advance.

SeñorAmor on

Posts

  • bowenbowen Sup? Registered User regular
    edited June 2008
    Every method I've tried required updating the DNS records (with the sometimes horrible lag time) and everything else suggests an extra A record to the other IP, which then causes problems if one goes down half your clients go to the downed site.

    I have heard offhand about some SRV record but haven't been able to find anything about that.

    EDIT:

    How about something like this?

    Simple Failover

    bowen on
    not a doctor, not a lawyer, examples I use may not be fully researched so don't take out of context plz, don't @ me
  • PirateJonPirateJon Registered User regular
    edited June 2008
    bowen wrote: »
    Every method I've tried required updating the DNS records (with the sometimes horrible lag time) and everything else suggests an extra A record to the other IP, which then causes problems if one goes down half your clients go to the downed site.

    This. When your ISP goes down, the last few hops of route to your sever goes with it. All of the DNS servers across the world still have the wrong IP so are trying that route. If you update the IP, you've just put in a new route. Typically DNS changes take 24-48 hours.

    For ISP redundancy, the majors typically use something like akami where there are multiple servers. Another option is BGP. Same destination, different paths to get there. but it takes some time and you don't want to mess it up - imagine if the two ISP's decide your network is the best path to route traffic between each other?

    If this is a big deal, consider asking for a redundant line from the main ISP.

    PirateJon on
    all perfectionists are mediocre in their own eyes
  • SeñorAmorSeñorAmor !!! Registered User regular
    edited June 2008
    Yeah, I guess I just thought that by having multiple A records (one for ISP1 and another with ISP2) that it'd try one, and then the next A record and so forth until it found one that worked (or ran out of A records to try).

    Seems to me that that would be the best way to do it.

    SeñorAmor on
  • bowenbowen Sup? Registered User regular
    edited June 2008
    PirateJon wrote: »
    bowen wrote: »
    Every method I've tried required updating the DNS records (with the sometimes horrible lag time) and everything else suggests an extra A record to the other IP, which then causes problems if one goes down half your clients go to the downed site.
    If this is a big deal, consider asking for a redundant line from the main ISP.

    We had this, and whenever one line went down, the redundant line did too. Not always the best situation for failover, unless for some reason it's tied to your specific ip. But yeah, definitely seems like you need to find some sort of service. I haven no experience with them so I can't offer anymore help.
    SeñorAmor wrote: »
    Yeah, I guess I just thought that by having multiple A records (one for ISP1 and another with ISP2) that it'd try one, and then the next A record and so forth until it found one that worked (or ran out of A records to try).

    Seems to me that that would be the best way to do it.

    I thought that too when I was doing them. You'd have thought someone would've answered that question when designing the system.

    bowen on
    not a doctor, not a lawyer, examples I use may not be fully researched so don't take out of context plz, don't @ me
  • SeñorAmorSeñorAmor !!! Registered User regular
    edited June 2008
    bowen wrote: »
    PirateJon wrote: »
    bowen wrote: »
    Every method I've tried required updating the DNS records (with the sometimes horrible lag time) and everything else suggests an extra A record to the other IP, which then causes problems if one goes down half your clients go to the downed site.
    If this is a big deal, consider asking for a redundant line from the main ISP.

    We had this, and whenever one line went down, the redundant line did too. Not always the best situation for failover, unless for some reason it's tied to your specific ip. But yeah, definitely seems like you need to find some sort of service. I haven no experience with them so I can't offer anymore help.

    Right; that's what I'm trying to avoid.

    Time Warner goes down, I still have my two DSL pipes coming in that I can use until TWC comes back up.

    SeñorAmor on
  • codetrapcodetrap Registered User regular
    edited June 2008
    If your IP address changes, so does your DNS. Updates are pretty fast.. under 10 minutes last time I checked it.

    http://www.dns2go.com/

    codetrap on
    < insert witty comment here>
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