Passwords on Linux Hosts

Rules for New Passwords on Linux Hosts

All linux hosts in the unixgroup use the following criteria to validate new passwords:

• Passwords must be at least 8 characters long
• Passwords must contain characters from 3 of the 4 character classes
• Passwords cannot contain dictionary word or user's login name

Password must be at least 8 characters long.
Passwords must be between 8 and 16 characters long. Examples:

Passwords must contain characters from 3 of the 4 character classes.
The 4 character classes are as follows:

1	uppercase letters	ABCDEFGHIJKLMNOPQRSTUVWXYZ
2	lowercase letters	abcdefghijklmnopqrstuvwxyz
3	digits	0123456789
4	non alpha-numeric chars	~!@#$%^&*()_+`{}|[]\:";'<>?,./

Note - An uppercase letter that begins the password and a digit that ends it do not count towards the number of character classes used.
Examples:

t07swee3	FAIL	Only 2 character classes - lowercase, digit
bu!!d0g86	PASS	3 classes - lowercase, digit, non alpha-numeric
6GwcmL99	PASS	3 classes - uppercase, lowercase, digit
$f3tchME	PASS	All 4 classes
Rum872ff	FAIL	2 classes - first uppercase doesn't count

Passwords must not contain dictionary word or user's login name.
Substituting digits or non alphanumeric characters for letters will make a dictionary word acceptable.
Examples:

aGoulD77	FAIL	contains user's login name "agould"
eXpired&	FAIL	contains dictionary word
eXp!r3d&	PASS	sufficiently garbled word

Helpful Hints
Most important: Do not use any password from this page! Everyone already knows these passwords.

• Pick something you can remember (avoiding your login name).
  "bulldog"
• Make sure it is at least 8 characters long.
  "bulldogg"
  
• Now pick one or more letters inside the word (not the end cap letters) and change to uppercase (or lowercase if you are already in uppercase).
  "bUlldoGg"
• Now pick one more more in addition to change to digits or non-alphanumeric characters.
  "bU11d0Gg"