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Posted on 2009-04-29
Medium Priority
Last Modified: 2012-05-06
I have win2003 installed with 2 DNS servers.
When I go to the properties of one zone, and click Nameservers, can you exactly explain me the star behind the IP address ?
Always when I want to have a delivery notification I get it from my own DNS2.
Why ?
Question by:Eprs_Admin
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Accepted Solution

Chris Dent earned 2000 total points
ID: 24258418

> When I go to the properties of one zone, and click Nameservers, can you exactly explain me the star
> behind the IP address ?

How much do you know about DNS already? Because this probably assumes rather a lot.

It means there's no glue and the IP address is the result of a lookup on the name.

Glue for the NS records means that you have Host (A) records for the name servers within the current zone. It is most important when dealing with Public Domains, if all you're doing is hosting an internal AD domain name for internal use in DNS then it's not all that important.

It exists for two reasons:

1. To speed up queries

 - If the Glue is present I will get the IP Addresses for the Name Servers at the same time as I get the NS Records

2. To break query deadlock

 - I want to lookup www.domain.com, and I find the Name Server is ns1.domain.com. If there's no Glue, I have to go back and try to lookup ns1.domain.com, but I have no way of finding the name servers for ns1.domain.com, this is a deadlock condition.

If your NS records looked like this:

domain.com.   IN NS  ns1.domain.com.
domain.com.   IN NS  ns2.domain.com.

Then Glue would be this:

ns1.domain.com.  IN A
ns2.domain.com.  IN A

If I asked for the Name Server records with those in place I would also get the Host (A) records in the response.

The Name Server names don't have to be in the same zone, but the glue would still be included, technically it's out of zone data, but important out of zone data. In this case it's only here to speed up resolution (because I don't have to look up the names to get the IP addresses for the name servers).

So you could have:

Zone Name: otherdomain.com

With these NS Records:

otherdomain.com.    IN NS  ns1.domain.com.
otherdomain.com.    IN NS  ns2.domain.com.

And still have Glue like this in the same zone:

ns1.domain.com.  IN A
ns2.domain.com.  IN A

You would also find Glue in delegation scenarios. Say I hosted "domain.com". Ideally the parent name servers, those responsible for .com, would provide Glue when handing out the NS Records for the domain.

So in our zone file for .com we might have:

domain.com.   IN NS   ns1.domain.com.
ns1.domain.com.   IN A

No other data for domain.com would be included in the com domain, only the NS record and the Glue.

> Always when I want to have a delivery notification I get it from my own DNS2.

Do what? You mean an e-mail delivery notification (failure)?

That's nothing at all to do with DNS if that is the case. Perhaps you could tell us about your E-mail system? :) Exchange? Is "DNS2" the server responsible for sending out your e-mail?


Author Comment

ID: 24295622
Thanks for your help.

Here is my present :

Author Closing Comment

ID: 31575829

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