CDNShark Documentation

Mailbox Password Rules

Mailbox passwords protect your inbox from people guessing their way in, so the mail server only accepts strong ones.

A password is accepted when it is

• a passphrase of 16 or more characters with at least 3 words, for example blue kettle river morning; or
• 10+ characters using lowercase, uppercase, digits and symbols; or
• 12+ characters using three of those four kinds; or
• 14+ characters using two of those kinds.

It is rejected when it

• is shorter than 10 characters, or longer than 128;
• contains a common word or pattern: password, qwerty, 123456, admin, welcome, letmein and similar;
• contains the mailbox name, your domain name, cdnshark or mail;
• relies on a year (like 2024) without being long and varied enough.

Tips

• A random passphrase of 3–4 unrelated words is both strong and easy to type on a phone.
• A password manager can generate and remember a random one for you.
• The strength meter in the form is a guide. Occasionally the server still rejects a password the meter allowed, for example one containing the domain name. If so, pick another.

To change a password: Change a Mailbox Password.