sendmail, 4th Edition

F=w

Check for valid user identity V8.7 and later

The sendmail program uses the getpwnam(3) routine (and can use others, such as LDAP) to determine whether a local address corresponds to a local account. If it does, the home directory for the user is copied into $z ($z on page 852). Then the full name of the user is extracted from the GECOS field of the passwd(5) file and placed into $x ($x on page 851).

Beginning with V8.7 sendmail, the information in the passwd(5) file is looked up only if the F=w delivery agent flag is set for the recipient’s delivery agent. In general, it must be present (set) for the local and any local-clone delivery agents but should be absent for all other delivery agents. For configuration files of levels lower than 6 (The V Configuration Command on page 580), the F=w delivery agent flag is automatically set for the local delivery agent.

Omitting the F=w delivery agent flag has several consequences:

• The recipient’s home directory is not looked up, and all user-level forwarding is prevented. Note that this voids all forwarding, even if the user’s home is defined as part of the ForwardPath option (ForwardPath on page 1034).

• The user’s full name is not looked up in the GECOS field of the passwd(5) file (the setting of the MatchGECOS option, MatchGECOS on page 1043, is ignored).

• The user-id and group-id of the recipient become unavailable, so the identity of the controlling user cannot be set to that of the recipient.

Note that if you are using Unix V7-style mailboxes ...