?
Solved

Domain name pointing to 2 different DNS servers

Posted on 2009-04-14
6
Medium Priority
?
238 Views
Last Modified: 2012-05-06
Hello guys,

When you register a domain name, let´s say at GODADDY.com and they ask you for the DNS servers, if one of the servers is down, the other DNS server is supposed to serve in order to browse the website?

Let's say I have DNS1 and DNS2, when a user try to browse my site, it will always point to DNS1 and if this one is down, it will automatically point to DNS2?

Thanks!
0
Comment
Question by:pvg1975
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 3
  • 3
6 Comments
 
LVL 71

Expert Comment

by:Chris Dent
ID: 24137230

Typically it load-balances over DNS servers (alternating requests to each DNS server).

The response will be cached on the system performing the query; not every client visiting the site will need to perform a full lookup of the name via your DNS servers.

Chris
0
 

Author Comment

by:pvg1975
ID: 24142650
Thanks Chris, so that means that if I run a database on one server, it should replicate on the other server as well?

Thanks.
0
 
LVL 71

Expert Comment

by:Chris Dent
ID: 24145718

It really depends what you've got set up. DNS operates entirely separately from any database engine or web service. However, if you have more than one web server (for fault tolerance) it would make sense to make sure the same content is available on both servers.

Chris
0
WatchGuard's M Series Appliances - Miecom Approved

WatchGuard's newest M series appliances were put to the test by Miercom.  We had great results and outperformed all of our competitors in both stateless and stateful traffic throghput scenarios! Ready to see how your UTM appliance stacked up? Download the Miercom Report!

 

Author Comment

by:pvg1975
ID: 24148438
Thanks Chris,

So if I set up 2 DNS servers in my domain name, lets say DNS1 and DNS2, can al http requests go straight to DNS1, and if this one is offline, go to DNS2?
0
 
LVL 71

Accepted Solution

by:
Chris Dent earned 2000 total points
ID: 24149865

It's not as simple as that I'm afraid.

You must split up DNS and HTTP. They operate on very different levels, DNS couldn't care less about HTTP and vice versa.

I think what you're looking for is Fail-Over should one of the web servers fail? You can use DNS to provide that, but it's not quite that simple, and gets more complex if the DNS service and web service share a server.

Normally you would have:

DNS1 (1.2.3.4) - Primary for domain.com
www.domain.com   IN A   1.2.3.4   TTL 300 (5 minutes)

DNS2 (1.2.3.5) - Primary for domain.com
www.domain.com   IN A   1.2.3.4   TTL 300 (5 minutes)

Note that both DNS servers are Primary, that means no automatic replication of changes between the zones. If we don't make both Primary you're pretty stuffed if you lose the Primary DNS Server, you won't be able to make changes (Secondary zones are Read Only).

Also notice that we have a low TTL set, 5 minutes. The TTL or Time To Live defines how long a requesting DNS server should remember your record before asking for it again.

If the web service on 1.2.3.4 fails you would have to manually change the IP address for www.domain.com and point it to 1.2.3.5. Clients would continue to go to 1.2.3.4 until you do.

You could do this:

DNS1 (1.2.3.4) - Primary for domain.com
www.domain.com   IN A   1.2.3.4   TTL 300 (5 minutes)

DNS2 (1.2.3.5) - Primary for domain.com
www.domain.com   IN A   1.2.3.5   TTL 300 (5 minutes)

In this situation while both servers are up load will be roughly split between the servers. It's very rough because you cannot control who queries DNS1 and who queries DNS2 while both are available.

If DNS1 were to fail it should drop off and only DNS2 would be responding, and therefore only DNS2 would be used as a Web Server (because that's the only version of the www record available). We're still reliant on the low TTL or 1.2.3.4 will be used if it's in memory / in the cache.

In short, while both are up you will not be able to control which web server is used unless you only have one www record.

Chris
0
 

Author Comment

by:pvg1975
ID: 24151241
Hi Chris. Thanks for your prompt answer :-)

I am looking to have 2 servers (Windows 2003) in two separate datacenters, and incase one of them fails, the other  one takes over.

I didn't know it was that difficult.

Thanks again

Paola.
0

Featured Post

Independent Software Vendors: We Want Your Opinion

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

I will assume you are running a non-server version of some sort of Windows throughout this article. There are many flavors of Windows since Windows Server 2000 - 2008, XP Home & Pro, Vista Home & Pro, and Windows 7 Starter, Home, Pro, Ultimate, etc.…
I've written instructions for one router type, but this principle may be useful for others of the same brand and even other brands of router. Problem: I had an issue especially with mobile devices that refused to use DNS information supplied via…
Michael from AdRem Software explains how to view the most utilized and worst performing nodes in your network, by accessing the Top Charts view in NetCrunch network monitor (https://www.adremsoft.com/). Top Charts is a view in which you can set seve…
In this video you will find out how to export Office 365 mailboxes using the built in eDiscovery tool. Bear in mind that although this method might be useful in some cases, using PST files as Office 365 backup is troublesome in a long run (more on t…
Suggested Courses

764 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question