Is it illegal to use private WHOIS for commercial email in California?
Michael Ko
Co-founder & CEO, Suped
Published 8 Aug 2025
Updated 18 Aug 2025
7 min read
Many email marketers and businesses are familiar with the concept of WHOIS privacy, a service designed to hide personal contact information from the publicly accessible WHOIS database. It is often seen as a beneficial way to reduce spam, unwanted solicitations, and even protect against identity theft. However, when it comes to commercial email, especially in a state with robust anti-spam laws like California, the use of private WHOIS can introduce unexpected legal complexities.
I’ve heard questions and concerns about lawsuits targeting commercial email senders who use private WHOIS for their domains. While the federal CAN-SPAM Act primarily focuses on deceptive headers and opt-out mechanisms, California’s state-specific anti-spam law (Business and Professions Code Section 17529 et seq.) can be more stringent. My goal here is to clarify whether using private WHOIS for commercial email in California crosses a legal line and what it means for your email deliverability efforts.
Understanding WHOIS privacy and its purpose
The WHOIS database is essentially a public directory listing the registered owner of every domain name. When you register a domain, your contact information, including name, address, email, and phone number, is typically made public by default. WHOIS privacy services allow domain registrants to replace their personal information with the contact details of a proxy service, thus shielding their identity from public view.
For many, this privacy is a valuable tool. It helps prevent data harvesting by spammers, reduces unwanted telemarketing calls, and offers a layer of protection against harassment or fraud. However, the intent behind using private WHOIS becomes critical when applied to domains used for sending commercial emails, where transparency and accountability are legally emphasized. We also often hear questions about how public versus private domain registration impacts email deliverability.
While there's no blanket federal law like CAN-SPAM that explicitly prohibits private WHOIS for commercial email, state laws can impose additional requirements. This is where California steps in with its own specific regulations aimed at preventing deceptive practices in commercial email.
The California anti-spam law
Deceptive Headers: Prohibits emails with false or misleading transmission information, making it difficult to identify the sender or the originating computer. This is where private WHOIS can become problematic if it is used to obscure the true sender’s identity.
Physical Address: Requires a valid physical postal address for the sender.
Opt-Out Mechanism: Mandates a clear and conspicuous unsubscribe option.
California's anti-spam law and deceptive headers
California’s anti-spam law, specifically Business and Professions Code Section 17529 et seq., aims to crack down on unsolicited commercial email (UCE) that uses deceptive means to hide the sender’s true identity. The law states that it is unlawful to advertise in a commercial email if the email contains “false or misleading header information” that would make it difficult to ascertain the actual sender. This is where private WHOIS can become a legal grey area, or even a direct violation.
Several court cases in California have addressed this issue. For instance, the case of Kleiner v. Gentiva Health Services, while older, highlighted that using WHOIS privacy services can indeed violate California statute if it prevents identification of the advertiser. The court focused on whether the use of such services effectively masks the true identity of the commercial email sender, thereby hindering consumers from identifying who is sending them unsolicited commercial email. If you use private WHOIS as a high-volume sender, this could expose you to significant risk.
The key distinction here is between general privacy protection and using privacy to evade accountability under commercial email laws. California’s law doesn’t prohibit WHOIS privacy services outright, but it targets those instances where the privacy service is utilized to obscure who is actually sending the commercial email, violating the requirement for traceable domain ownership for commercial communications.
CAN-SPAM act
Federal Law: Applies nationwide across the United States.
Focus: Primarily on accurate header information, clear identification of advertising, a valid physical postal address, and a functional opt-out mechanism.
WHOIS Privacy: Does not explicitly prohibit private WHOIS, as long as other sender identification requirements are met (e.g., in the email content itself as mandated by the FTC).
California anti-spam law
State Law: Applies to emails sent to or from California residents.
Focus: Stronger emphasis on “deceptive header information” and preventing obscuration of the actual sender.
WHOIS Privacy: Can be interpreted as a violation if it contributes to making the true sender untraceable, thereby falling under the deceptive header clause.
The court's interpretation and implications
The interpretation of California’s anti-spam law has evolved through various court decisions. While the law does not explicitly mention private WHOIS, appellate courts have found that using such services can contribute to violating the law’s prohibitions against deceptive header information. The core principle is that commercial emails must allow a recipient to easily identify the sender and their physical address.
For instance, a ruling in Guthy-Renker v. Windows Web Solutions emphasized the need for a “traceable domain” for commercial emails. If WHOIS privacy makes the domain registrant untraceable for the purpose of identifying the actual sender of commercial email, then it could be deemed a violation. This legal stance impacts how email blacklists (or blocklists) operate, as they often rely on WHOIS data for investigations, and also complicates efforts for law enforcement to track down malicious senders.
While many domain registrars offer WHOIS privacy as a default or recommended service, businesses sending commercial email into or within California need to consider these specific state laws. It highlights a tension between individual privacy protection and the need for accountability in commercial communications.
Example WHOIS lookup (Public Registration)
WHOIS example.com
Registrar WHOIS Server: whois.example-registrar.com
Registrar URL: http://www.example-registrar.com
Updated Date: 2024-01-15T10:00:00Z
Creation Date: 2023-01-15T10:00:00Z
Registrar Registration Expiration Date: 2025-01-15T10:00:00Z
Registrar: Example Registrar, Inc.
Registrar IANA ID: 1234
Registrar Abuse Contact Email: abuse@example-registrar.com
Registrar Abuse Contact Phone: +1.1234567890
Domain Status: clientTransferProhibited https://icann.org/epp#clientTransferProhibited
Name Server: ns1.example-dns.com
Name Server: ns2.example-dns.com
DNSSEC: unsigned
URL of the ICANN WHOIS Data Problem Reporting System: http://wdprs.internic.net/
>>> Last update of WHOIS database: 2024-02-14T12:00:00Z <<<
Best practices for California-based commercial emailers
To ensure compliance with California’s anti-spam laws, and to maintain good email deliverability, I recommend prioritizing transparency for domains used in commercial email. While WHOIS privacy offers benefits, the legal risks in California for commercial senders are noteworthy. It’s always safer to err on the side of full disclosure for your domain registration information if that domain is central to your commercial email campaigns.
I also suggest ensuring that your commercial emails always include accurate sender identification in the email headers and body. This means clearly identifying the business or entity sending the email, providing a valid physical postal address (as required by both CAN-SPAM and California law), and offering a straightforward unsubscribe mechanism. You should make sure your unsubscribe process is easy to use, without requiring a login.
Being proactive about compliance helps avoid potential legal challenges and contributes to better sender reputation. When mailbox providers and recipients can easily verify the sender's identity, it builds trust, which is crucial for effective email marketing. Remember, your primary goal is to reach the inbox, and adhering to legal requirements is a fundamental step in that direction.
Element
CAN-SPAM
California Anti-Spam Law
Deceptive Headers
Prohibited (from Federal Trade Commission)
Prohibited, with specific interpretation on untraceable senders
Physical Address
Required
Required
Opt-Out Mechanism
Required, clear and conspicuous
Required, clear and conspicuous
Private WHOIS
Generally permitted if other requirements met
Potentially problematic if it obscures actual sender, leading to untraceability
Views from the trenches
Best practices
Always ensure a clear, valid physical postal address is included in commercial emails.
Make unsubscribe options prominently visible and easy to use without requiring logins or multiple steps.
For domains used heavily in commercial email, consider using public WHOIS registration.
Review your email sending practices against both federal CAN-SPAM and California's specific anti-spam laws.
Common pitfalls
Relying solely on CAN-SPAM compliance and ignoring stricter state-specific regulations.
Assuming WHOIS privacy provides full anonymity for commercial email activities.
Using generic or misleading sender information that doesn't accurately reflect your business.
Failing to provide easily accessible contact information beyond what's in the WHOIS record.
Expert tips
Verify your email authentication (SPF, DKIM, DMARC) to prove sender legitimacy.
Segment your email lists carefully to avoid sending to unengaged or potentially problematic recipients.
Keep abreast of changes in email regulations, as laws are continually evolving.
Consult with legal counsel specializing in email and privacy law for specific advice on your practices.
Expert view
Expert from Email Geeks says a key challenge is that many relevant cases, like US v. Kilbride, predate GDPR and the widespread adoption of default privacy proxy services for domain registration, which complicates current interpretations.
2024-02-13 - Email Geeks
Marketer view
Marketer from Email Geeks says they wonder if lawsuits are specifically about having private WHOIS, or if it's about sending emails from domains that happen to have private WHOIS and also lack clear unsubscribe options or other identifying information.
2024-02-14 - Email Geeks
Legal takeaway for California commercial emailers
While private WHOIS registration offers significant privacy benefits for domain owners, its use for domains central to commercial email activities in California is fraught with legal considerations. California’s anti-spam law, unlike the federal CAN-SPAM Act, has been interpreted by courts to require a higher degree of sender traceability, particularly when it comes to preventing deceptive header information.
Ultimately, the legality hinges on whether the private WHOIS service effectively obscures the actual sender's identity to the point of being deceptive or untraceable for compliance purposes. For businesses operating in California, embracing transparency in your email practices, including public domain registration for commercial sending, is a prudent step to ensure legal compliance and foster a positive sender reputation.
Does not explicitly prohibit private WHOIS, as long as other sender identification requirements are met (e.g., in the email content itself as mandated by the FTC).
Prohibited (from Federal Trade Commission)
