[PLUG] DNS And site available

wes plug at the-wes.com
Fri Nov 28 00:04:32 UTC 2008


On Thu, Nov 27, 2008 at 10:17 AM, linux-yug <linux-yug at xprt.net> wrote:

> On Thu, 2008-11-27 at 02:30 -0800, linux-yug wrote:
> > On Thu, 2008-11-27 at 02:04 -0800, drew wymore wrote:
> > > On Thu, Nov 27, 2008 at 12:39 AM, linux-yug <linux-yug at xprt.net>
> wrote:
> > >
> > > > On Thu, 2008-11-27 at 00:13 -0800, drew wymore wrote:
> > > > > On Wed, Nov 26, 2008 at 9:51 PM, linux-yug <linux-yug at xprt.net>
> wrote:
> > > > >
> > > > > > Can I set my DNS up so if my Primary server is down at
> xx.yy.zz.aa
> > > > > >
> > > > > > It automatically goes to site b..  pp.qq.rr.aa  ????
> > > > > >
> > > > > > Where server A is in Flordia and Server B is in P-Town.???  ON
> very
> > > > > > different Static IPs'  ???
> > > > > >
> > > > > > TIA
> > > > > >
> > > > > > Linux-yug
> > > > > >
> > > > > > _______________________________________________
> > > > > >
> > > > >
> > > > >
> > > > > DNS servers or web servers? When you set  up DNS to do round robin
> to
> > > > load
> > > > > balance. Otherwise you'll need to update DNS to point at another
> server
> > > > if
> > > > > it's for web services.
> > > > > _______________________________________________
> > > >
> > > >
> > > > I didn't make that clear did I????
> > > >
> > > > I want to have a second web server standing by in the event the
> primary
> > > > web server goes down.. Like now...  My primary web server is down..
> Loss
> > > > of power....And power won't be back for another two days..
> > > > But, I have  perfectly good, rsynced web server at an alternate
> location
> > > > with another IP...
> > > >
> > > > How do I get that to come on line.. Now that the primary is down?
> > > >
> > > > Thanks
> > > >
> > > > linux-yug..
> > > >
> > > > _______________________________________________
> > > > PLUG mailing list
> > > >
> > >
> > >
> > > Update your primary and or secondary name servers (assuming primary is
> on
> > > the dead box) to point to the web server that is still alive.
> > > _______________________________________________
> >
> >
> >
> > Ok..
> >
> > I was thinking that was the obvious answer..
> >
> > I just recently got a second IP..
> >
> > Thanks
> >
> > Linux-yug
> >
> > _______________________________________________
>
> Wait...
>
> How does it know to go to ns2???
>
> Right now I have
>
> ns1  xxx.yyy.zzz.aaa
> ns2  xxx.yyy.zzz.aaa
>
> If I change to
>
> ns1 xxx.yyy.zzz.aaa
> ns2 bbb.ccc.eee.fff
>
>
> How does it know to use ns2  cause ns1 is down???
>
> IT checks???
>
> The dns server actually check to see if ns1 is up ..
> and if not checks  ns2????
>
> Thanks
>
> linux-yug
>

Each person that browses to your site does an nslookup for your domain,
which eventually reaches one of your name servers (ns1 or ns2). If the first
one it tries doesn't respond, it tries the next one. Only problem is, there
is no way to guarantee that everyone will try ns1 first. It all depends on
the resolver, and in most cases we have no control over it, or even know
what software is being used. That being said, I would guess around 80% of
the time they go to ns1 first.

However, if you have no reason not to have your site up in both places at
once, then using ns1 to point to one and ns2 to point to the other is just
fine. This just gets a little messy when you do things like dynamic
content.. you have to keep databases synchronized and such.

-wes



More information about the PLUG mailing list