DNS - Troubleshooting

In this article you will learn:

• How to find the cause of a DNS problem
• How to troubleshoot DNS problems:
  • Servers
  • Records in general
  • Records pointing to the web
  • Records directed to mail
• Frequently Asked Questions

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Diagnosing DNS problems

A broken or incorrectly set DNS can manifest itself as a broken domain, i.e. a browser message about the unavailability of the site with the code DNS_PROBE_FINISHED_NXDOMAIN. Alternatively, the website displays old content or errors of the web hosting provider (e.g. suspended or deleted service), no emails, etc.

You can use a tool in the customer administration to perform a system diagnostic on a domain. You can find instructions in the Domains - Diagnostics article.

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DNS troubleshooting

DNS problems fall into two categories: either the DNS servers, where domains get their data to function properly, or the DNS records (usually pointing the domain to the web or email) are not set up correctly.

DNS servers

Common problems with DNS servers include:

• Unavailable DNS servers. Here it is usually a problem with the domain and its settings, which are discussed in the article Domains - Troubleshooting.
• Ongoing change of DNS servers. The propagation of a specified DNS server change over the Internet is relatively slow, typically within 6 to 48 hours. To avoid inconsistent behavior or service outages during this time, make sure that the same DNS records are set up on both sets of DNS servers. Disable DNSSEC while the changes are in progress.
• Changes to records on incorrect DNS servers. If the set records are not being overwritten even after tens of minutes, make sure you are setting up the correct provider. WEDOS DNS records have no effect on the operation of a domain that uses another provider's DNS servers.

DNS records

Common problems with DNS records in general include:

• Time required to rewrite records. For WEDOS DNS records, allow approximately 30 minutes for a TTL value of 300. For higher TTL values, the propsing may take longer.
• Incorrect record name. Different DNS service providers specify records in different ways. When entering record names in WEDOS DNS, avoid entering the character @ (instead of this character, leave the field Name empty) and the domain itself (the system will fill in the main domain name automatically).
• Conflict of subdomains. If you rely on routing subdomains with a record named *, make sure that no other records conflict with this routing. Subdomains for which there is a specific record of any type, a record named * they don't use. Set up all routing on such subdomains directly.
• Incompatible record settings. The system warns of incorrect or incompatible record settings before a new record or change is saved. Troubleshoot the problem according to the instructions in the error message.

DNS site records

The web is served by DNS records of type A, AAAA, CNAME and ALIAS. Common problems with DNS settings for the Web include:

• Insufficiently set DNS records. When entering or changing DNS records, make sure that you are entering all the records that your web hosting provider requires. This is usually the records for the main domain (A, AAAA, ALIAS) and all subdomains (name *) or at least a subdomain www.
• AAAA legacy service records. When switching to a web host that uses only Type A records, delete all AAAA records with the same names as the modified Type A records.

DNS records of emails

For the correct functioning of e-mails, it is necessary to set the MX type records, DKIM and SPF records. Common problems with DNS settings for emails include:

• MX records with the name. MX records are usually entered for the main domain (@domena.tld), the field Name so leave it blank.
• MX records from different providers. If you are changing MX records to a different provider, delete any remaining records from the original provider.
• Incorrect SPF record. Make sure you have one SPF record. If you need to enter SPF records from multiple mail service providers, combine them all into one by following the instructions in Emails - SPF record.

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Frequently Asked Questions