Often intruders can simply guess a password to break into your system. It is easy to guess, for example, that an xTuple database will have a user called "admin". If the admin password is "admin", or "1234" or "asdfasdf", or another obvious pattern, it will take only a few tries to enter your database with full admin privileges.
Therefore, it is best to require all users to follow these guidelines for creating a strong password.
A strong password has:
At least 15 characters
Uppercase letters
Lowercase letters
Numbers
Symbols, such as ` ! " ? $ ? % ^ & * ( ) _ - + = { [ } ] : ; @ ' ~ # | \ < , > . ? /
A strong password is NOT:
Your login or username
Your name, your friend’s name, your family member’s name, or a common name
A dictionary word
Like your previous passwords
Your date of birth
A keyboard pattern, such as "qwerty," "asdfghjkl," or "12345678"