Understanding DNS : Part - II
In my previous discussion about Understanding DNS, you learned most of the basic things related to DNS. In this post i want to elaborate more about DNS. Let's start...
There are so many records associated with a DNS Server. Name resolution process does not happen in a proper way with out these records.
As you know the DNS server main purpose is to resolve the host names to IP's and vice versa.
- A Record : Contains information about IP address. It is helpful in resolving host names to IP addresses.
- PTR Record : Pointer record, contains information about host name. It is helpful in resolving IP address to hostname.
- CNAME Record : Alias of A Record. It is helpful in giving multiple names to a single host. Which means, the same host is able to provide multiple services. In that case, for segregation of service and to communicate with that service we need to give different names to each service. Even though these services are hosted on a single server, but we can send our request to the target service. CNAME record was helpful in identifying and communicating with that service on that server.
- MX Record : It is a record helpful in identifying the mail server in a DNS domain (for that organization)
- NS Record : It is a record helpful in identifying the DNS server in a DNS domain (for that organization)
- SRV Record : This record is created when we install a service which is DNS dependent. It is automatically generated and will be associated with a specific IP address. It is called as Service record.
- SOA Record : Start of Authority record, this is not a record associated with any IP address. But it is associated with a number, which determines the update number. What ever the update, when ever it is done this number will be incremented.
These are the records associated with each and every server in this world. A fact is that " DNS is the biggest database in the world and that is the only one which gets updated every second " And this database is not located at a single place, it is spread across the world in different places like, different companies, different ISP's, different homes etc. And the name resolution process is explained in my previous post Understanding DNS. That is the reason why, a DNS request goes to different location to get the correct answer.
In my next article related to DNS, i will discuss about HOW TO TROUBLESHOOT DNS PROBLEMS, KEEP VISITING OR SUBSRCIBE NOW TO GET THE LATEST POST UPDATES.
I hope this is informative for you, i would like to thank you for reading this article.
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