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How to Check DNS Records for the Domain

Check DNS records for the domain


You recently changed your DNS records, switched web host, or started a new website: you are in the right place! DNS Checker provides the free DNS lookup service to check Domain Name System records against a specified list of DNS servers in multiple regions worldwide. Run a quick DNS propagation lookup for any hostname, and check the DNS data collected from all available DNS servers to ensure that the DNS records are fully propagated.

How do DNS records propagate?


Updating your DNS records can take up to 72 hours for the changes to take effect. During this period, ISPs worldwide update their DNS cache with the new DNS information for your domain.

However, due to the different DNS cache levels, after changing the DNS records, some visitors may be redirected to the old DNS server for some time, and others can see the website from the new DNS server shortly after the changes. You can perform a lookup for A, AAAA, CNAME, and additional DNS records.

Why does DNS propagation take time?


Let’s say you change your domain name servers and request to open your domain on a web browser. Unfortunately, your request will not go to hosting directly.

Each ISP node first checks the DNS cache, whether it contains DNS information for that domain. In case if it is not there, then it will search for it to save it for future use to speed up the DNA search process.

Thus, the new name servers will not be published immediately – ISPs have different levels of cache refresh, so some will still have the old DNS information in their cache.

But if the new DNS changes are not reflected after this period, you go for a DNS health check to ensure your DNS changes are up to the mark and follow the standards.

How does the DNS process work?


Let’s say you asked to open the URL in your web browser bar.

The web browser will first checks in its local cache if it contains the IP address of the requested domain. Then, it will also send the request to the name resolution server if it does not exist.

The name resolution server checks its cache against this request. If it fails to find the IP address of the requested domain, it will send this request to the root server.

The root server can only contains the server’s IP address with the TLD (Top Level Domain) information. It will redirect the name resolution server to the TLD server containing the .com information.

TLD server also provides the server’s IP address (authoritative servers for the requested URL to the name resolution server.

The name resolution server caches this information for a specified period (TTL) and passes that information to the requesting computer.

The client computer builds the connection to the authoritative server (which contains the requested URL for the requested content and stores the IP address information in its browser for further use.

Why is DNS not published?


ISPs all over the world have different caching levels. For example, the DNS client or server may store information that the DNS records in its DNS cache. This information is temporarily cached, and the DNS servers will pass on the updated DNS information when the TTL (Time To Live) expires.

If the domain name does not exist, What will happen?


The DNS server will display a name error, also known as the NXDomain response (for non-existent domain), indicating that the query domain name does not exist.

What port does DNS use?


The DNS uses both TCP and UDP port 53. However, the most commonly used port for the DNS is UDP 53. It is used when the client computer communicates with the DNS server to resolve the given domain name. When using UDP 53 for DNS, ensure the maximum query packet size is 512 bytes.

TCP 53 is mainly used for zone transfers and when the query packet exceeds 512 bytes. This is true when DNSSEC is used, which adds additional overhead to the DNS query packet.

What is a DNS failure?


The DNS failure means that the DNS server cannot convert the domain name to an IP address in the TCP/IP network. This failure may occur within the company’s private network or the Internet.


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