Each time a WHOIS lookup runs, the data may come from either the registrar or the registry, depending on the type of WHOIS the TLD uses. Understanding the difference between thin and thick WHOIS helps you predict how domain locks and contact changes behave on your domains.
What is a thin WHOIS lookup?
A thin WHOIS lookup returns limited technical data from the registry, including the sponsoring registrar, the domain status, and the creation and expiration dates. The remaining data, including the contact details, is stored directly with the holding registrar (OpenSRS). Examples include .com and .net.
What is a thick WHOIS lookup?
A thick WHOIS lookup holds all the data at the registry, including the administrative, technical, and owner contact details, along with the sponsoring registrar and registration status. Because the data is handled at the registry level rather than the registrar, there are restrictions on how the domain lock affects contact changes. Examples include .info, .biz, and .name.
How this affects your domains
The WHOIS type determines how domain locking interacts with contact changes:
WHOIS type | Where contact data is held | Effect of domain lock on contact changes |
|---|---|---|
Thin | At the registrar (OpenSRS) | The domain lock does not prevent contact changes. |
Thick | At the registry | The domain lock prevents contact changes until the domain is unlocked. |
Tip: If you need to update contact details on a thick-WHOIS domain that is locked, unlock it first, make the change, then lock it again.
Next steps
- See Locking or Unlocking Domains for how lock status is handled.
- Use the Tucows Web WHOIS to look up a domain.
Questions? Contact OpenSRS Support.
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