Upgrading and Repairing Networks

Common Login Problems

The most common problem users encounter when logging in to a Unix system is summed up by the following error message:

login incorrect

This message doesn't convey a great deal of information to the user, but it usually indicates one of the following conditions:

• There is no user account in the /etc/passwd file for this username.

• The password entered by the user is not correct.

• The home directory for the user (as specified in the password file) does not exist.

In the first instance, the administrator might not have gotten around to creating a record for the user in the /etc/passwd file. It is more likely that the user entered the username incorrectly. Remember that, in the Unix operating system, usernames and passwords are case sensitive. For example, if your username is LukeKurtis, entering lukekurtis or LUKEKURTIS will not work.

When you're choosing passwords, it is a good idea to choose one that is not easy for others to guess. Unfortunately, this sometimes means that it is also easy for a user to forget. Choosing a text string that contains both uppercase and lowercase letters, along with numeric and alphabetic characters, is a good idea. When you receive the login incorrect error message, check to be sure that you are really entering the password as it was originally set up.

In all cases, one of the first things to check is that the Caps Lock key is not on. On a notebook, you may also need to double-check the settings of your Num Lock key, because the right half of the keyboard often acts as a 10-key when Num Lock is enabled.

If the account is new, it is possible that the user's home directory has not been created or the administrator has not set the correct permissions on the directory to allow the user access to it. Using a script file to create new user accounts can help prevent this problem. Coding all the necessary commands by a script file will prevent the problems caused when an administrator creates a new account in a hurry and forgets a step or two.