Greywell Cyber

Legal

Terms of Use

Last updated 12 October 2026.

Who We Are

greywellcyber.com is run by Greywell Cyber Ltd, registered in England and Wales, company number 16835578, registered office 124 City Road, London EC1V 2NX. You can reach us at solutions@greywellcyber.com.

Using This Site

By using this site you accept these terms. If you do not, please do not use it. You may read, print and share pages for your own use and for teaching, with a link back to us. Please use the site within our acceptable use policy.

The Free Tools

The subnet calculator, password generator, route summariser, security headers checker and quiz are provided free of charge, as they are, for learning and planning. We test them and fix what we find, but we do not promise that every result is right for your network or your situation.

  • Check any result before you rely on it in a production network, a firewall rule or a change request.
  • The quiz is revision practice. It is not an official exam or affiliated with any exam body.
  • The security headers checker reads what a public website sends back. It is not a security assessment of that site. Only point it at sites you are allowed to check.
  • We may change, pause or withdraw a tool at any time.

If you find a wrong answer, tell us at toolfeedback@greywellcyber.com and we will fix it.

Your Free Account

Registration is free and open to anyone with an email address. If you are under 13, please ask a parent or carer before you register. When you have an account:

  • Keep your sign in codes to yourself. Anyone with a code can sign in as you while it lasts.
  • One account per person, registered with an email address that is yours to use.
  • You can download your data or delete your account at any time on your account page. Deleting it ends these account terms between us.
  • We may suspend or close an account that breaks our acceptable use policy, telling you why unless the law or the safety of others stops us.
  • We may change or withdraw the quiz or training. If we close member accounts altogether, we will email you at least 30 days before and give you time to download your data.

How we handle your account data is in our privacy policy.

Our Liability

Nothing in these terms limits liability that cannot be limited by law, including for death or personal injury caused by negligence or for fraud, and nothing affects your statutory rights as a consumer.

If you use the site as a consumer, for your own learning rather than for a business: we are responsible for loss you suffer that is a foreseeable result of our failing to use reasonable care and skill. We are not responsible for loss that was not foreseeable, and because the site is for personal learning, we are not responsible for any loss of profit, business or business opportunity.

If you use the site in the course of a business: the site and tools are free and provided as they are, without any promise about their results beyond what these terms say. To the extent the Unfair Contract Terms Act 1977 allows, we are not liable for loss of profit, revenue, data or business, or for any indirect or consequential loss, and our total liability to you for everything arising from your use of the site and tools is limited to £100.

Client Work

Paid work is never governed by these terms. Every engagement runs under written terms agreed before any work starts, setting out what is in scope, what it costs and who is responsible for what.

Links to Other Sites

We link to other sites, such as the NCSC and the ICO, because they are useful. We are not responsible for what they say or do.

Intellectual Property

The text, design and code of this site belong to Greywell Cyber Ltd unless we say otherwise. The passphrase word list is the EFF Large Wordlist, used under the Creative Commons Attribution 3.0 licence and credited on the password generator page.

Changes and Law

We may update these terms; the date at the top shows when. These terms are governed by the law of England and Wales, and the courts of England and Wales may hear any dispute. If you are a consumer living in Scotland or Northern Ireland, you keep the protection of the law where you live and may bring proceedings in your home courts.