Blog / DNS servers and possible errors

DNS servers and possible errors

by SW Team

In order to talk about them, we must first understand: What are DNS and what do they consist of?

You still don't have your own domain to manage your DNS? If so, we recommend you to take a look at the domain offers we offer at SWHosting.


What is DNS?

DNS stands for Domain Name System, and is the system used on the Internet to convert domain names, such as, into IP addresses, such as This method makes the addresses easier for people to remember, in contrast to the numerical sequences that represent IP addresses.

Every computer or device that connects to the Internet requires a unique IP address to be accessible from anywhere on the network, so DNS is essential.

Now that we know what DNS is, the question arises: How does it work?

How do DNS work?

DNS operate under a hierarchical and decentralised structure. Queries start at local DNS servers that cache common IP addresses. If they do not have the address, they are directed to higher-level DNS servers, which contain the Internet's root directory.

The root servers have knowledge of the DNS servers responsible for each top-level domain (.com, .net, etc.). These, in turn, know the servers of the second level domains, and so on, until they reach the DNS server of the target website hosting the IP address.

Once the IP is located, it is returned to the browser to load the page. DNS facilitates the location and loading of websites in a transparent way, translating domain names to IPs.

If the primary DNS server stops working, there is usually another secondary server working independently, typically on a different network, to ensure that the service is not interrupted. When the primary server fails, the secondary server kicks in and handles all website requests.

Now that we understand the theory, we may have some practical questions or doubts, for example:

How do I find out which DNS points to my domain?

There are many ways to find out which DNS your domain points to, but all of them are based on a Whois query.

Whois is a protocol based on TCP requests and responses that is used to look up information in a database about a specific domain, such as its status and other relevant information. Sensitive information can be hidden to prevent third parties from querying it.

You can perform a Whois query directly from your terminal (in case you have such a command installed on your operating system), however, you can find websites that provide the same information in a simpler way, for example:

Global DNS Propagation Center

Another thing to keep in mind is that not necessarily all DNS records have to point to the same server, which is why DNS zones and their multiple records exist. If you are curious about this, we invite you to visit our manual about DNS records and how to manage them in case you have SWPanel as your personal management panel.

Manage DNS records

How can I assign or modify the DNS to which my domain points?

In case you have your domain in SWHosting, you can modify the DNS to which your domain points in a very simple way, following one of the two manuals attached below.

In case your domain is in SWHosting, but my service is external:

External DNS configuration

In case both your domain and your service are in SWHosting:

How to configure my domain's DNS servers (Nameservers)

What types of errors can be generated at the DNS level?

Although these types of errors are not common, it is a good idea to identify them. Some of them are:

  • NXDOMAIN error: This means that the requested domain does not exist. It occurs when you try to access a domain that has never existed or has been removed from your hosting.

  • DNS server not authoritative: This error occurs when the DNS server queried does not have the authority to provide information about the requested domain. It is usually due to an incorrect configuration of the DNS zones for that domain.

  • Time To Live (TTL) exceeded: DNS records have a defined time to live (Time To Live) that indicates how long they can be cached. If this time is exceeded, the record must be queried again to the authoritative server. Too low a TTL can overload DNS servers by constantly forcing queries against it.

  • Server Error: Occurs when there is a problem with the DNS server that prevents the request from being processed due to server overload or failure.

  • Resolution loop: Occurs when DNS servers redirect records to each other without reaching an authoritative response, resulting in an infinite loop.

  • DNS poisoning: Occurs when a DNS record is maliciously altered to redirect traffic. DNS providers usually implement measures to prevent this type of manipulation.

  • Duplicate records: Some DNS records (e.g. CNAME, SPF, DKIM, etc...) cannot coexist with other records of the same type, as they conflict with each other.

  • Misconfigured DNS zone: This is a common error caused by the user configuring DNS records and introducing syntax errors.

How can I fix DNS errors I encounter?

Proper DNS functionality is crucial to the presence and accessibility of your website. If the DNS servers assigned to your domain are not functioning properly or are unable to resolve, users attempting to access your site over the Internet will encounter difficulties.

When the DNS associated with your website fails, visitors will receive a "page not found" or "404 Page not found" error message when trying to access the site.

DNS-related errors are rare, unless there has been an incorrect assignment, which is the most common case.

The typical message when a domain has no DNS record is:

⚠️ DNS server does not respond.

These errors, usually identified as DNS_PROBE_POSSIBLE, can be caused by connection difficulties between the web browser and the site you are trying to access or resolve.

It is possible that the "DNS server not found" error message is caused by failures in the TCP/IP or DHCP protocols, especially on fibre networks, or it could even be due to problems with your Router or Modem device.

If you encounter this problem when trying to open a website in the Firefox browser, one option that may be useful to rule out the problem is to try accessing the same site using another browser, such as Google Chrome, Opera, Bing, Safari, or others.

It is important to make sure that you always use the most stable version of your preferred browser to rule out any problems related to using an outdated or unsupported version.

Another solution that should always be tried for this type of problem is to clear or flush the DNS cache, as it can sometimes become obsolete and needs to be cleared in order to update it.

You can do this from your computer's terminal or console by typing the command:

  • On Windows:

    ipconfig /flushdns
  • On GNU/Linux:

    sudo service network-manager restart

    Or depending on the Linux distribution also:

    sudo /etc/init.d/nscd restart
  • On macOS:

    sudo killall -HUP mDNSResponder

If you suspect that the problem may be related to your Router/Modem, first try resetting your connecting device, and then check if you can access the Internet and browse normally.

If the problem persists, but you can access the Internet from other devices (such as your mobile phone), it is possible that the problem is specifically related to your connecting device. In this case, consider contacting your Internet Service Provider (ISP) to resolve the issue.

Also, check if you can browse while connected to the Router/Modem via a network cable. If you normally connect via wifi, it is possible that there are saturation problems in the channel assigned to your wireless network or that the distance between your device and the wifi access point is too great.

If you have any kind of firewall, try temporarily disabling the Firewall and its protection functions, and then try browsing the Internet again to see if the problem persists.

Ultimately, if none of these suggestions have helped you, you can always assign other DNS to your Internet gateway device, for example Google's:

Google DNS for IPv4 (the current standard):


Google DNS for IPv6 (new standard):

  • 2001:4860:4860::8888
  • 2001:4860:4860::8844

You can make this type of configuration from your Router or Modem device, as long as it allows specific settings in its configurations.

Now that you know how DNS works, do you need a service that has a DNS zone to point your domain to? Take a look at the hosting solutions we offer you: