in.uucpd is the server for supporting UUCP connections over networks.

in.uucpd is invoked by inetd(1M) when a UUCP connection is established (that is, a connection to the port indicated in the "uucp" service specification) and executes the following protocol. See services(4):

1. The server prompts with login:. The uucico(1M) process at the other end must supply a username.
2. Unless the username refers to an account without a password, the server then prompts with Password:. The uucico process at the other end must supply the password for that account.

If the username is not valid, or is valid but refers to an account that does not have /usr/lib/uucp/uucico as its login shell, or if the password is not the correct password for that account, the connection is dropped. Otherwise, uucico is run, with the user ID, group ID, group set, and home directory for that account, with the environment variables USER and LOGNAME set to the specified username, and with a -u flag specifying the username. Unless the -n flag is specified, entries are made in /var/adm/utmpx, /var/adm/wtmpx, and /var/adm/lastlog for the username. in.uucpd must be invoked by a user with appropriate privilege (usually root) in order to be able to verify that the password is correct.

in.uucpd uses pam(3PAM) for authentication, account management, and session management. The PAM configuration policy, listed through /etc/pam.conf, specifies the modules to be used for in.uucpd. Here is a partial pam.conf file with entries for uucp using the UNIX authentication, account management, and session management module.

uucp    auth requisite          pam_authtok_get.so.1
uucp    auth required           pam_dhkeys.so.1
uucp    auth required           pam_unix_auth.so.1

uucp    account requisite       pam_roles.so.1
uucp    account required        pam_projects.so.1
uucp    account required        pam_unix_account.so.1

uucp      session required      pam_unix_session.so.1

If there are no entries for the uucp service, then the entries for the "other" service will be used. If multiple authentication modules are listed, then the peer may be prompted for multiple passwords.

/var/adm/utmpx

accounting

/var/adm/wtmpx

accounting

/var/adm/lastlog

time of last login

See attributes(5) for descriptions of the following attributes:

inetd(1M), uucico(1M), pam(3PAM), pam.conf(4), services(4), attributes(5), pam_authtok_check(5), pam_authtok_get(5), pam_authtok_store(5), pam_dhkeys(5), pam_passwd_auth(5), pam_unix(5), pam_unix_account(5), pam_unix_auth(5), pam_unix_session(5)

All diagnostic messages are returned on the connection, after which the connection is closed.

user read

An error occurred while reading the username.

passwd read

An error occurred while reading the password.

Login incorrect.

The username is invalid or refers to an account with a login shell other than /usr/lib/uucp/uucico, or the password is not the correct password for the account.

The pam_unix(5) module might not be supported in a future release. Similar functionality is provided by pam_authtok_check(5), pam_authtok_get(5), pam_authtok_store(5), pam_dhkeys(5), pam_passwd_auth(5), pam_unix_account(5), pam_unix_auth(5), and pam_unix_session(5).