DNS zones

What is a DNS zone?

DNS zone is a text file that provides mappings of host names to their IP addresses. The DNS server knows how to manage those records to properly resolve host names on the Internet or local network. When a web site is open in a browser the DNS query is made to retrieve the site’s IP address, then the server with that IP address is contacted and the host name (domain) is requested from that server. This is how the site opens up in the browser. Here’s what a typical DNS zone would look like:


$ORIGIN MyDomain.com.
@ 3600 IN SOA MyDomain.com. root.MyDomain.com. (
2014112401 ; serial
7200 ; refresh
3600 ; retry
86400 ; expire
3600) ; minimum

;; NS Records (These are you name servers where the DNS zone resides)
MyDomain.com. 300 IN NS NS.SOMEWHERE.example.com.

;; MX Records (These point to your email server addresses and control the incoming email)
MyDomain.com. 300 IN MX 0 MyDomain.com.protection.outlook.com.
MyDomain.com. 300 IN MX 10 berkshireworks-org.mail.protection.outlook.com.

;; TXT Records (Additional records that help to direct some services to them)
MyDomain.com. 300 IN TXT “v=spf1 include:spf.protection.outlook.com -all”
MyDomain.com. 300 IN TXT “v=spf1 include:spf.protection.outlook.com –all”

;; CNAME Records (Aliases for the host names. For example www record can be pointed to that or email host)
msoid.MyDomain.com. 300 IN CNAME clientconfig.microsoftonline-p.net.
cdc7443769ed2f65c9f9c739a80e05e5.MyDomain.com. 300 IN CNAME fcf490f0093f414908db808538213296a2216b84.comodoca.com.
autodirect.MyDomain.com. 300 IN CNAME discover.outlook.com.

;; A Records (IPv4 addresses. This is used for all main hosts)
MyDomain.com. 300 IN A
mail.MyDomain.com. 300 IN A
www.MyDomain.com. 300 IN A
*.MyDomain.com. 300 IN A

Most DNS related issues are related to the DNS zone configuration. Make sure all IP addresses and host names are entered correctly here.