Configuration DNS Primaire et Secondaire | Windows server 2008 R ~ R2
You have a probably come across the terms “primary DNS server” and “secondary DNS server”.
Actually a DNS server (the computer/software) is not specifically “primary” or “secondary”.
A DNS server can be primary for one zone (domain) and secondary for another.
The DNS specifications require that each domain name is served by at least 2 DNS server for redundancy.
This may seem a little silly – especially if you run your DNS, web, and mail servers all on the same machine – if this machine goes down, it doesn’t really matter that the backup DNS server still works.
But many registrars (companies that register domain names) still require at least 2 DNS servers.
This requirement has been somewhat relaxed lately, and depending which registrar you use, you may only need to specify one DNS server.
NOTE: If your registrar lets you use only one DNS server, some DNS testing tools may still flag this as an error.
NOTE: Registrars requiring 2 DNS servers sometimes refer to these as “primary” and “secondary”.
This has absolutely nothing to do with the actual primary/secondary functionality, and it doesn’t matter in which order you enter your DNS servers for the domain name. This is just a list of servers, and there could be 1, 2, or any number of DNS servers listed for a domain name.
By definition, a primary DNS server holds the “master copy” of the data for a zone, and secondary servers have copies of this data which they synchronize with the primary through zone transfers at intervals or when prompted by the primary.
Only one DNS server should be configured as primary for a zone, but you can have any number of secondary servers for redundancy.
Both primary and secondary servers for a zone serve exactly the same data to clients.
Because of this you could easily “simulate” a secondary server on a single computer with 2 IP addresses.
Simply configure the zone (as primary), and the server will function as both the primary (on one IP address) and secondary (on the other IP address).
by Walid Belhanafi
windows server dns
