Make sure to employ security best practices for passwords, such as the following:
Length: The minimum recommended length is 6 characters. A secure password is at least 8 characters; longer passwords are better.
Complexity: A secure password contains a mixture of letters and numbers. It should contain both uppercase and lowercase letters and at least one numeric character. Adding numbers to passwords, especially when they are added to the middle and not just at the beginning or the end, can enhance password strength. Special characters such as &, $, and > can greatly improve the strength of a password.
Do not use recognizable words, such as proper names or words from a dictionary, even if they are bookended with numbers. Do not use personal information, such as phone numbers, birth dates, anniversary dates, addresses, or ZIP codes. Do not invert recognizable information; inverting bad passwords does not make them more secure.
Uniqueness: Do not use the same passwords for all servers. Make sure to use separate passwords for each server so that if one server is compromised, all of your servers are not immediately at risk.