How Wrong DNS Values Can Affect Your Website

DNS is the critical service that runs behind the scenes and enables the modern Internet to function properly. It tells browsers, email servers, and other services where on the internet a domain resides. It does this by mapping domain names to specific IP addresses. That is just one of its core functions.

DNS does a lot more than that, and it does everything by using something we call DNS records. They contain the information (i.e., which domain name maps to which IP address, etc.) that makes DNS work.

When those records contain incorrect values, the problem can range from a few users seeing an old version of your website to your entire site becoming unreachable.

The tricky part is that DNS problems do not always look like DNS problems. A visitor may simply see a server error, a browser may report that the domain cannot be found, or only users in certain regions may have trouble accessing the site.

In this article, we will cover some of the major problems your site can run into due to incorrect DNS record values and how you can avoid them.

What Happens When a DNS Value Is Wrong?

Every DNS record has a specific job. For example, an A record points a domain to an IPv4 address, while a CNAME record points a hostname toward another hostname. MX records control where email for the domain is delivered, etc.

If one of these values is incorrect, DNS resolvers may return an incorrect destination or fail to resolve the hostname altogether.

For example, suppose your website is hosted on:

203.0.113.50

but your A record contains:

203.0.113.80

The difference is only one number (8 instead of a 5 in the last octet), but this completely changes the IP address.

If you publish that record with that mistake, visitors looking for the domain will be sent to the wrong server. Since that server does not host your website, those visitors will receive an error or see an unexpected site.

And that's just one example of how things can go wrong for your site. Now let's look at more ways that incorrect DNS values can cause problems for your site.

Common Problems Caused by Incorrect DNS Records

1. Your Website May Become Unreachable

As we saw in the previous example, a website can become unreachable if its A and CNAME records have incorrect values.

The end user who attempts to visit such a site may encounter errors such as "This site can't be reached" or ERR_NAME_NOT_RESOLVED.

These kinds of errors and blunders usually happen during big changes. For example, a website may see an uptick in such errors after:

• Moving to a new hosting provider
• Changing its server's IP address
• Adding a new subdomain

And basically, what happens is that someone who was responsible for updating the DNS records probably did something accidentally, like:

• Deleting a DNS record
• Entering an IP address incorrectly

Even a single misplaced digit can be enough to break the connection.

The only solution is to check your DNS records after every major change, such as getting a new hosting plan and adding a subdomain.

2. Visitors May Reach the Wrong Server or See the Wrong Site

A DNS record does not know which server you intended to use. It simply returns the value configured for it. So, if a website runs on multiple servers, then users may see a slightly different version of the site. This isn't uncommon or too bad because functionally the site is the same.

The problem occurs if your domain points to an old hosting account. If the incorrect IP address directs visitors to that, they may see an outdated website or nothing at all. In some cases, they may see a default hosting page instead.

This kind of mix-up usually happens during website migrations when DNS records haven't propagated completely. So users end up seeing an old version of the site because they are using outdated records for DNS resolution.

There is no solution for this. Domain managers can at most monitor their DNS propagation to see which regions might be affected and make a social media announcement that the site may not be working in those areas for a while.

3. Email Can Stop Working

DNS is not just resolving domain names to IP addresses; it is also controlling how emails are handled for your domain. It does this via a variety of records. Let's take a look at some of them.

MX records tell mail servers where to deliver messages for your domain. If these records point to the wrong mail provider, incoming email can fail or be delivered somewhere unexpected.

TXT records such as SPF, DKIM, and DMARC are also important for email authentication and security. They help protect your domain's emails against spoofing and sniffing.

They also have extremely long values because they contain cryptographic keys, so it is not difficult to accidentally add the wrong values for these records.

Incorrect values in these records can damage your email sender reputation, deliverability, and kill your ability to do email outreach.

The solution is to be extra careful when handling such records and double-checking their values when updating or creating them.

4. Subdomains Can Break

Your main domain and its subdomains can have separate DNS records, so a DNS mistake does not necessarily take down your entire website. One part of your site may continue working normally while another becomes unreachable.

For example, a website might use:

• example.com, the main website
• www.example.com, an alternative hostname for the main site
• blog.example.com, a blog hosted on a separate server
• shop.example.com, an online store running on a different platform

Each of these can have its own DNS configuration. For instance, example.com might point to your main web server, while shop.example.com uses a CNAME that points to an e-commerce platform.

If you accidentally enter the wrong value for blog.example.com, the main website can remain perfectly accessible while the blog stops loading. Visitors may see a DNS error, reach the wrong server, or be redirected somewhere unexpected.

This can also happen when a subdomain is moved to a new hosting provider. If its DNS record still points to the old server, users will continue being sent to the previous location even though the main domain has already been updated.

That is why DNS troubleshooting should not stop at checking the root domain. If only one part of your website is failing, check the DNS record for the specific subdomain as well.

How to Check Whether DNS Values Are Correct

The first step is to compare the DNS value you expect with what DNS resolvers are actually returning.

This is where a propagation checker can be useful.

You can use a DNS checker tool, such as WhatsMyDNS.me, to check how a domain's DNS records resolve across DNS servers in different locations.

The tool supports common record types including:

• A
• AAAA
• CNAME
• MX
• NS
• TXT
• SOA
• CAA

and others.

For example, if you recently moved your website to a new server, you can do a domain to IP lookup to see the domain's new IP addresses. Then compare the returned value with the configured new server's IP address.

Any discrepancies mean that either new records haven't propagated fully or something was added incorrectly. The issue may be related to DNS caching, incomplete DNS changes, a CDN or proxy, or another DNS configuration.

In either case, you can simply open your domain management portal to check the values of all records that have discrepancies.

How to Fix an Incorrect DNS Value

Once you identify the problem, go to the DNS provider that is authoritative for your domain and correct the record.

Also, before changing anything, check the following:

1. The record type, i.e., A, CNAME, MX, TXT, etc. The point is to make sure you are editing the right record.
2. The hostname. Make sure you are editing the correct domain or subdomain. Unnecessary changes in the wrong domain will only create more problems.
3. The value. Double-check the IP address, hostname, or other record data carefully before publishing the records.
4. The nameservers. Make sure you are editing DNS at the provider actually serving your domain; otherwise, the changes won't go live.
5. The TTL. Understand that due to higher TTLs, cached responses may continue showing an older value for some time.

Do not keep changing records simply because you cannot immediately see the new result. DNS caches can take time to expire, and repeated changes can make troubleshooting harder.

Final Thoughts

A small DNS mistake can have a surprisingly large effect. A wrong A record can make a website unreachable, an incorrect CNAME can break a subdomain, and an improperly configured MX record can disrupt email.

The good news is that DNS problems are often straightforward to diagnose once you know what to look for. Check the authoritative records, compare them with the values you expect, and use a global DNS propagation checker such as WhatsMyDNS to see how those records are resolving in different locations.