Solved

Windows DNS forwarders

Posted on 2013-05-15
5
383 Views
Last Modified: 2013-05-24
I would like to know the difference between the DNS Standard Forwarders and Root hint forwarders. they sound to me redundant.

The conditional forwarder makes sense to me...for instance , you are telling the client if you want to resolve this specific zone name I will send you (Forward) to this DNS (the one specified in conditional forwarders.

but Standard forwarders, seems the same to me as the Root Hints.....it is saying If you need to resolve a name space that I am not aware of I will send you to this DNS .... I guess Root Hint will take care of that without configuring standard forwarder.Please correct me if I am wrong.

Thanks
0
Comment
Question by:jskfan
[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
5 Comments
 
LVL 12

Assisted Solution

by:Henk van Achterberg
Henk van Achterberg earned 100 total points
ID: 39168931
You are correct but using root hints you are sure that you will get the results as any other server at the internet will get using root hints.

When using a forwarder you may not know the configuration of that server and you may get other results as when using root hints.

I know ISP's which replace NX DOMAIN with their own search landing page (bleg!)
0
 
LVL 19

Assisted Solution

by:strivoli
strivoli earned 100 total points
ID: 39168966
You are correct.

Sometimes, it is better using a forwarder instead of root hints for performance reasons. Since DNS response times are very important for the overall Internet Browsing Speed, many (admins) find out that setting the ISP's DNS server as forwarder performs much better than root hints.
0
 
LVL 26

Accepted Solution

by:
DrDave242 earned 300 total points
ID: 39169009
Forwarders allow you to specify DNS servers that your server will contact for queries that it can't answer.  Typically you'd use your ISP's DNS servers as forwarders, since they're likely to give you a pretty quick response, but you can use any server you want.

The root hints list is a list of the authoritative servers for the DNS root zone.  Like forwarders, these can be used to answer queries that your DNS server can't answer.

One main difference between the two lies in how the queries are conducted:

Root hints use iterative queries, in which your server sends a query to one of the root servers, which responds with a referral to a top-level domain (like .com or .net) server that can potentially answer that query.  Your server then queries that server, which will then respond with another referral to a server that's authoritative for the domain you specified in the query (experts-exchange.com, for example).  This process continues until your server queries a server that's actually authoritative for the specific FQDN in your query, which will then either provide the record requested or state that it doesn't exist.

When you use forwarders, your server issues a recursive query to the forwarder.  A recursive query basically tells the forwarder, "You do the legwork, and I'll wait here for an answer."  The forwarder then goes through basically the same process as shown above  (with some extra steps added in, like checking its own cache) and sends the final answer back to your server.

In a nutshell, your server does more work if you use root hints, but that amount of work is pretty trivial, and you're not likely to notice a difference in performance either way unless you're performing a very large number of DNS queries.

Using forwarders can obviously cause a problem if you only specify one and it goes down for whatever reason.
0
 
LVL 19

Expert Comment

by:strivoli
ID: 39187524
Any feedback is welcome. Please help us keep EE clean. Close the question if we did help, delete it if we didn't help. Thank you.
0
 

Author Closing Comment

by:jskfan
ID: 39195721
Thank you
0

Featured Post

On Demand Webinar: Networking for the Cloud Era

Did you know SD-WANs can improve network connectivity? Check out this webinar to learn how an SD-WAN simplified, one-click tool can help you migrate and manage data in the cloud.

Question has a verified solution.

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

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…
While rebooting windows server 2003 server , it's showing "active directory rebuilding indices please wait" at startup. It took a little while for this process to complete and once we logged on not all the services were started so another reboot is …
In this video, viewers will be given step by step instructions on adjusting mouse, pointer and cursor visibility in Microsoft Windows 10. The video seeks to educate those who are struggling with the new Windows 10 Graphical User Interface. Change Cu…
Monitoring a network: how to monitor network services and why? Michael Kulchisky, MCSE, MCSA, MCP, VTSP, VSP, CCSP outlines the philosophy behind service monitoring and why a handshake validation is critical in network monitoring. Software utilized …

734 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