The Domain Name System (DNS) maps domain names to numerical IP addresses. This helps people identify the website they are trying to visit instead of having to enter a numerical sequence. DNS errors are some of the most common problems resellers will run into.
This guide outlines common DNS problems you may encounter and provides steps to resolve or troubleshoot them.
1. Domain serverHold Error
The serverHold error is one of the most common errors a reseller encounters. While there are many causes, the most common reason this occurs is when the domain has been suspended by a registry, which is often due to missing DNS information.
There are many ways to address this problem, but the simplest is to go to the domain’s Name Servers and swap them. For example, if your Name Servers were:
- ns1.greengeeks.net
- ns2.greengeeks.net
Simply replace the 1 and 2, respectively, and this will solve the problem.
Another way to fix this error is to make sure that the hosting package assigned is created. It is possible to assign a domain a package that does not exist. If this is the case, simply change the package to one that does, or create a new one with that name.
2. DNS Fails to Resolve
If a DNS fails to resolve, this occurs because the information added to the DNS records is incorrect. It can be something as simple as misspelling the domain name, or something bigger, like forgetting to create an AAAA record, which would cause the DNS resolution to fail for clients that use IPv6.
The fix for this is to go to the DNS records and find what is wrong. Double-check spelling, ensure that the proper records have been created, such as A, AAAA, CNAME, and so on. It is very common for resellers to misspell a new customer’s domain name, so always check that first.
3. DNS TTL Errors
Every DNS record has a Time-To-Live (TTL) assigned to it. The TTL is the number of seconds that the record will live for. Once that value runs out, the DNS record will cease to exist, which will cause problems for the site. It is essentially an expiration date for the DNS record.
If the DNS TTL is set too high, then the changes to a website may take longer to be reflected. As such, most DNS records last for 6 hours. To fix any errors related to TTL, simply check the TTL and ensure it is not set to a high value.
For reference, the highest value possible is 24 hours, which is 86400. However, no TTL should be set to this.
4. DNS_PROBE_FINISHED_NXDOMAIN
This DNS error makes your site completely inaccessible. This occurs when the system couldn’t find the IP address for the requested domain. Users who try to access your website will see a message like “This site can’t be reached” if they are using Google Chrome.
There are a variety of things that can cause this error to occur, which can make fixing it a bit tricky. For the best results, try the following actions:
- Ensure the Domain Name is spelled correctly
- Flush DNS Cache
- Confirm the A record is correct
- Renew your IP address
5. Propagation Delays
During site migrations, it may take time for updated content to appear, or your emails may bounce. This is normal and is the result of the changes not propagating quickly. While there are some things that you can control, many of these issues will fix themselves given more time.
To attempt to speed the process up, you can start by double-checking the DNS TTL. During a site migration, it is recommended to set the TTL to between 300 and 3600 seconds. This will help speed up content updating on the site. You can also try flushing the local and browser DNS cache.
Unfortunately, there are situations where the cause is delays in the global DNS root servers. In these cases, you just need to wait patiently.
6. Email Bouncbacks, Spam Flags, and Delivery Failures
If customers are experiencing email bouncebacks, spam flags, or delivery failures, there is a good chance the reason is that the MX record is misconfigured. Most commonly, this is caused by typos found within the records or by duplicate records existing.
Common fixes for this problem include:
- Fixing typos with records
- Deleting duplicate records
- Point MX records to A records
- Confirm domain ownership
7. Refused DNS Error
The Refused DNS error occurs when a DNS server has intentionally rejected your request. This can occur for several reasons, such as having your IP address blocked by IP filtering or country-wide blocks. It can also be caused by misconfigured DNS settings or firewall rules.
Steps that you can take to resolve this issue include verifying that the nameservers from your hosting provider and registrar match. Alternatively, try switching to automatic or public DNS settings. If a customer is being blocked by IP filtering, you will need to adjust those settings.
If it is by country, the customer may need to use a VPN.
8. DNS Timeout
A DNS Timeout occurs when a request is sent, but a response is not received within the allotted time. This can be due to several factors, such as Firewalls blocking you, network issues, high latency, or unresponsive DNS servers. These can go unnoticed, as they do not have an actual error code.
Fixes for this issue include flushing the DNS cache, reducing TTL to shorten wait times, or using a CDN to combat geographical issues, such as being very far away from a web server. If all else fails, it may just be a bad connection with your ISP or the wi-fi you are using.
9. CNAME Loop Detected
This error occurs when the CNAME record points to another CNAME that points back to itself in an endless loop. This will block customers or users from being able to access the domain in any way until the issue is resolved.
To resolve the issue, you need to end the loop by checking the DNS records and examining where the CANME records lead to. This could be a result of a duplicate file being called upon, and you simply need to delete it to solve the issue.
10. ERR_TOO_MANY_REDIRECTS
This error occurs when there are too many redirects within the A or CNAME records. This is more likely caused by an endless loop that is created between the two, which is very similar to the CNAME Loop Detected error.
The solution is similar; start by verifying your existing A and CNAME records and see where each one leads. You will likely find a loop that needs to be corrected.
11. FORMERR (Format Error)
The format error occurs when a server receives a request it cannot understand or process. This usually happens when a newer server sends a request to an older one. Essentially, the older one can’t handle the newer options and suggests an issue with the customer’s DNS protocol.
If this error is encountered, you will need to do a deep dive and investigate the DNS records to confirm whether it is on the website’s end or the customer’s. An update will be required for older servers to be able to handle modern requests.
12. Split-Horizon DNS issue
A split-horizon DNS issue occurs when a network uses different DNS records for external and internal users of the same domain. Typically, internal users may get locked out because the DNS points to external addresses, or vice versa.
The solution is to ensure that the DNS records are pointing to the correct location. It is highly recommended to check the website and content by accessing it from different networks to ensure that the correct users have access to it.