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man pages section 5: File Formats

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Updated: Wednesday, February 9, 2022



d_passwd - dial-up password file




A dial-up password is an additional password required of users who access the computer through a modem or dial-up port. The correct password must be entered before the user is granted access to the computer.

d_passwd is an ASCII file which contains a list of executable programs (typically shells) that require a dial-up password and the associated encrypted passwords. When a user attempts to log in on any of the ports listed in the dialups(5) file, the pam_dial_auth(7) service module looks at the user's login entry stored in the passwd(5) repository, and compares the login shell field to the entries in d_passwd. These entries determine whether the user will be required to supply a dial-up password.

Each entry in d_passwd is a single line of the form:




The name of the login program that will require an additional dial-up password.


An encrypted password. Users accessing the computer through a dial-up port or modem using login-shell will be required to enter this password before gaining access to the computer. These are in the same format as the password field described in shadow(5).

d_passwd should be owned by the root user and the root group. The file should have read and write permissions for the owner (root) only.

If the user's login program in the passwd file is not found in d_passwd or if the login shell field in passwd is empty, the user must supply the default password. The default password is the entry for /usr/bin/sh. If d_passwd has no entry for /usr/bin/sh, then those users whose login shell field in passwd is empty or does not match any entry in d_passwd will not be prompted for a dial-up password.

Dial-up logins are disabled if d_passwd has only the following entry:



Example 1 Sample d_passwd file.

Here is a sample d_passwd file:


The password fields may be generated using the pwhash(1) command.



dial-up password file


list of dial-up ports requiring dial-up passwords

See Also

pwhash(1), dialups(5), passwd(5), shadow(5), pam_dial_auth(7)


When creating a new dial-up password, be sure to remain logged in on at least one terminal while testing the new password. This ensures that there is an available terminal from which you can correct any mistakes that were made when the new password was added.