Monday, April 15, 2013

What is a Glue Record?

SkyHi @ Monday, April 15, 2013

Glue Records

This article offers a definition of a Glue Record, a description of why a Glue Record is need and how they are resolved through DNS, and how to create a Glue Record through the CloudAccess.net Client Area.

What is a Glue Record?

Why are Glue Records needed?

How to create a Glue Record

What is a Glue Record?

A Glue Record is the IP Address of a name server at a domain name registry. Glue Records are fundamental parts of DNS records because they help to resove DNS servers at a core level. If you would like to change the name servers for a site, you ll have to provide the Glue Records for the new name serves. Without them, a domain name will not work because anyone requiring the DNS information will be stuck in a loop. There is a cyclic dependency of circular referencing. Circular references exist where the name servers for a domain can t be resolved without resolving the domain they re responsible for. Glue Records are additional A records that allow the DNS client to locate name servers. 

When are Glue Records needed?

For example, let s say your domain (yourdomain.com) is using ns1.nameserver.com and ns2.nameserver.com as name servers, but gridfast.net also uses ns1.nameserver.com and ns2.nameserver.com as name servers. This is how the cyclic dependency is created. To break the cycle, DNS systems use Glue Records. 
You can also understand Glue Records by understanding A Records. An A record (an A address) is a DNS record that can be used to point your domain name and host names to a static IP address. For example, the A record for gridfast.net includes ns1.gridfast.net and ns2.gridfast.net and their IP addresses. These servers can be reached directly without any further resolution. For a domain name like CloudAccess.net, however, the root DNS servers pass the ns1.gridfast.net and ns2.gridfast.net nameservers, and a further chain of resolution is needed to resolve the DNS. This is when a Glue Record is needed.


REFERENCES
http://www.cloudaccess.net/infrastructure-networking/66-servers-dns/318-glue-records.html