Subdomain Finder (2025)

FAQs

What is a subdomain finder? ›

Subdomain Finder scans the DNS records and supplementary databases to analyze the domain's hierarchy. Our subdomain scanner checks: DNS records (NS, MX, TXT, AXFR) DNS enumeration.

While subdomains can work well for some companies, depending on their goals, a subdirectory is often a better choice for SEO.

Google's search operators make it easy to narrow down the search to find more subdomains. We can use the "site" operator in the search bar to find all the subdomains that Google has indexed for a domain. Google also supports the minus operator to exclude any subdomains we are not interested in.

You can usually locate it in the root or footer section of the website. For example, the XML sitemap URL could be “www.example.com/sitemap.xml“. Once you click on the sitemap, you will find all pages & subpages of a website.

The most common subdomain is “www” or “world wide web.” The subdirectory points users to the main directory of a website—in other words, where your homepage and other core pages live. Other subdomains work to create distinct parts of a site. For example, Google's root domain is www.google.com.

However, Google treats subdomains as separate sites.

While “blog.example.com” and “example.com” may share a root domain, Googlebot will view them as distinct domains and crawl and index them accordingly.

This helps you to create a different look, feel, and functionality for your online store than your main website. You'll come across subdomains like these all over the internet. They're incredibly common. To see whether your site is using any subdomains, crawl your website with Semrush's Site Audit tool.

A domain can have up to 500 subdomains. You can create multiple levels of subdomains such as store.product.yoursite.com, test.forum.yoursite.com, etc. Each subdomain can be up to 255 characters long, but for multi level subdomains, each level can only be 63 characters long.

According to Google, subdomains and subdirectories are seen as equal when it comes to indexing and ranking. That said, real-world case studies show that subdirectories tend to rank faster and more effectively than subdomains on the first page of the search engine results page (SERPs).

A sitemap is a file of your site's pages, links and other information that helps Google read and index your site. Each subdomain has its own dedicated sitemap that needs to be submitted to Google individually.

How to list all DNS records in nslookup? ›

Using nslookup online is very simple. Enter a domain name in the search bar above and hit 'enter'. This will take you to an overview of DNS records for the domain name you specified.

There are some subdomains that are defined for virtually every domain name, such as www, and others that are very common, like shop or mail. But by going through and trying a DNS query using `dig`, `nslookup`, or `host` for as many possible subdomains, you might find some hidden ones.

To identify DNS entries within your organization that might be dangling, use Microsoft's GitHub-hosted PowerShell tools "Get-DanglingDnsRecords". This tool helps Azure customers list all domains with a CNAME associated to an existing Azure resource that was created on their subscriptions or tenants.