I tried to setup a login password using lower & upper case letters of the form User followed by numbers (where User is my User name and the password is thus composed of at least 8 characters). I've also tried initials with numbers. I keep on getting not good enough. I haven't been able to find a definitive set of rules for the login password. Could anyone point me to a definitive set of rules for login passwords?


If you have no real interest in security you can avoid having to enter your password by having the system login automatically.

If you however do want a secure password (which would be sensible in most cases) the following guidelines are recommended.

Strong Passwords

Applications, and libraries exist for your Ubuntu system to assist in generating, or enforcing strong passwords. A strong password is defined as any password which meets the following criteria:

    At least fifteen (15) characters in length.
    Does not contain your user name, real name, organization name, family member's names or names of your pets.
    Does not contain your birth date.
    Does not contain a complete dictionary word.
    Is significantly different from your previous password.

    Should contain three (3) of the following character types.
        Lowercase Alphabetical (a, b, c, etc.)
        Uppercase Alphabetical (A, B, C, etc.)
        Numerics (0, 1, 2, etc.)
        Special Characters (@, %, !, etc.) 

Source: https://help.ubuntu.com/community/StrongPasswords

Edit: If you want to enforce strong passwords or relax password requirements all this is configurable by editing /etc/security/pwquality.conf The file is heavily commented and pretty self-explanatory. Details on the respective options can be found on the man page

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  • I found that it will accept a 10 character password, of the form word@acronym – John Rose Mar 24 '17 at 17:01
  • @JohnRose Well, I suppose should and must are sometimes 2 different things. Personally, I recommend strong passwords (and never using the same one for different things) – Elder Geek Mar 24 '17 at 20:06
  • It's irritating that Canonical have decided on rules for login passwords. IMO it's none of their business what strength of passwords I want to use. It would be Ok for warnings about passwords being weak. – John Rose Mar 26 '17 at 17:05
  • @JohnRose It's not a Canonical thing. You'll run into default security settings on any Linux distro. You can change anything you don't like though (whether ill advised or not) See my edited answer. – Elder Geek Mar 27 '17 at 4:07

From https://help.ubuntu.com/lts/serverguide/user-management.html:

By default, Ubuntu requires a minimum password length of 6 characters, as well as some basic entropy checks

So it should be fine. If you have access to /etc/pam.d/common-password you could comment a word TEMPORARY and use it til you get your account properly set up. (If you don't I recommend a live cd)

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