[NTLUG:Discuss] "Back up dns server"?

[m m]

> Date: Tue, 4 Dec 2007 23:41:49 -0600> From: wwalker at bybent.com> To: leroy_tennison at prodigy.net; discuss at ntlug.org> Subject: Re: [NTLUG:Discuss] "Back up dns server"?> > To simplify:> > 1. All your DNS servers should _always_ return the same information for> all hosts. (There are rare cases where this is not true, but m m's> problem is not one of these rare cases.)> > 2. Assuming that what m m really wants is failover to a second web server> when the first one goes down, there are a few solutions:> > A. Have two web servers running all the time. Have DNS always giving out> both addresses. Web browsers will choose which one they go to at random.> This is the method little companies like Google and Amazon use:> > wwalker at elephant:~$ host www.google.com> www.google.com is an alias for www.l.google.com.> www.l.google.com has address 64.233.169.99> www.l.google.com has address 64.233.169.147> www.l.google.com has address 64.233.169.104> www.l.google.com has address 64.233.169.103> wwalker at elephant:~$ 
 
 
What happens if a client A's request goes to 64.223.169.99 and  64.223.169.99  id down?
Won't the client A get error message? 
Or the Client A goes to another ip such as 64.233.169.103?
> > > C. Set up a proxy server on the host at 4.5.6.7 and have it forward all> traffic to 1.2.3.4 until it sees 1.2.3.4 is down, then it points all> traffic to another web server (or itself).> If 4.5.6.7 can be depended on to be up, use it and forget> about the web server that is behind an unreliable firewall> or connection.
 
This one seems a sulation, is there any example in the real world? 
 
> > > -- > > Wayne Walker> > # Code comments are lies waiting to happen> > wwalker at bybent.com Do you use Linux?!> http://www.bybent.com Get Counted! http://counter.li.org/> Perl - http://www.perl.org/ Perl User Groups - http://www.pm.org/> Jabber: wwalker at jabber.gnumber.com AIM: lwwalkerbybent> IRC: wwalker on freenode.net> > _______________________________________________> http://www.ntlug.org/mailman/listinfo/discuss
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