Contact Form 7 can validate the syntax of a website address. A separate DNS lookup can show whether a hostname currently has particular DNS records. These checks answer different questions and neither proves that a website is safe or that a domain can be registered.
Validate the field you actually need
Use a URL field when you need a website address, and explain the expected format. If the field is required, use Contact Form 7’s required URL field. Add a custom validation rule only when there is a clear business need. See the official custom-validation guide for the supported filter approach.
What a DNS check can tell you
A lookup checks DNS records at the time of the request. A missing record, an unavailable resolver or a temporary error does not establish that a domain is unregistered. A registered domain may have no website or no A record.
Check registration separately
Use the relevant registry or registrar to check whether a domain can be registered. ICANN Lookup provides registration data for supported domains. Confirm availability and price with the registrar before placing an order.
The earlier version of this article used an inverted DNS test as an availability check. That approach was unreliable and has been removed. Contact Yasa about domain registration, DNS or Cloudflare setup.
