DNS Propagation Check

Provides free dns lookup service for checking domain name server records against a randomly selected list of DNS servers in different corners of the world.

Explaining Zone Files and Record Types

Zone files and record types are two terminologies that are commonly used when talking about the Domain Name System (DNS). What do these terminologies mean?
Zone files are the methods with which name servers store the information they know about certain domains. In other words, every domain that a server knows about is stored in a zone file so that whenever queries are brought to the server by resolving name server, answers to the recursive queries will be promptly provided. This occurs because the server has already stored the required information in a zone file.
This does not mean that a server can supply answers to all queries it receives about several domains; it only can provide answers for those it has their information stored in Zone Files. And if the server cannot help the resolving name server with the information it is seeking, it directs it to the next server.
A zone file is described as a specific “DNS Zone” for a particular domain, which is a subset of the entire Domain naming system. And each file may contain records for the domain in question, from which all required information/data can be retrieved.
The zone’s $Origin represents the highest level of authority of the domain by default. This means that if a user is looking for all information about microsoft.com, it’s configuration is set to microsoft.com as the $Origin. However, sometimes the queries sent to the server about microsoft.com has time-limited answers: Designated as $TTL “Time to live” information, you can only have access to this kind of information for a certain period of time. When its “time to live” expires, such information will not be available on the zone file and records. It does matter how long you searched for this information, you won’t get it because it is already taken off the internet.

Different Types of Records

Different types of records exist within the zone file, and highlighted below are some significant/essential ones:
  • SAO Records: SOA stands for “Start of Authority” records, and it is the most essential and the first real record type within a DNS’ zone file. It is a complex structure that reveals information about a domain’s primary master name server, root of the zone, serial number of the zone file, the email address of the administration for the zone file, the refresh and retry time intervals for the zone, the time of expiry of the information, and the time it takes for the server to cache the domain’s information.
  • A and AAAA Records: These two records map a host to an IP address. The “A” record is meant to map a host to an IPv4 IP address, while “AAAA” record maps a host to an IPv6 address.
  • CNAME Records: CNAME records mainly give a nickname to your server, and defines whether it should be specified as an “A” or “AAAA” records’ server.
  • MX Records: These records are used to define email messages correctly so that mails can arrive at your domain accordingly.
  • NS Records: This kind of record defines the name servers that are utilized for this zone.
  • PTR Records: These records are used to define a name associated with an IP address. They are the direct opposite of A and AAAA records.