37.20 Retrieving Mail from Remote Mailboxes

Some sites use a method called POP for accessing users' inbox data instead of storing the data in inbox files. The Emacs movemail can work with POP if you compile it with the macro MAIL_USE_POP defined. (You can achieve that by specifying ‘--with-pop’ when you run configure during the installation of Emacs.)

The Mailutils movemail by default supports POP, unless it was configured with ‘--disable-pop’ option.

Both versions of movemail only work with POP3, not with older versions of POP.

No matter which flavor of movemail you use, you can specify POP inbox by using POP URL (see section movemail program). A POP URL is a “file name” of the form ‘pop://username@hostname’, where hostname is the host name or IP address of the remote mail server and username is the user name on that server. Additionally, you may specify the password in the mailbox URL: ‘pop://username:password@hostname’. In this case, password takes preference over the one set by rmail-remote-password. This is especially useful if you have several remote mailboxes with different passwords.

For backward compatibility, Rmail also supports two alternative ways of specifying remote POP mailboxes. First, specifying an inbox name in the form ‘po:username:hostname’ is equivalent to ‘pop://username@hostname’. Alternatively, you may set a “file name” of ‘po:username’ in the inbox list of an Rmail file. movemail will handle such a name by opening a connection to the POP server. In this case, the MAILHOST environment variable specifies the machine on which to look for the POP server.

Another method for accessing remote mailboxes is IMAP. This method is supported only by the Mailutils movemail. To specify an IMAP mailbox in the inbox list, use the following mailbox URL: ‘imap://username[:password]@hostname’. The password part is optional, as described above.

Accessing a remote mailbox may require a password. Rmail uses the following algorithm to retrieve it:

1. If the password is present in mailbox URL (see above), it is used.
2. If the variable rmail-remote-password is non-nil, its value is used.
3. Otherwise, if rmail-remote-password-required is non-nil, then Rmail will ask you for the password to use.
4. Otherwise, Rmail assumes no password is required.

For compatibility with previous versions, the variables rmail-pop-password and rmail-pop-password-required may be used instead of rmail-remote-password and rmail-remote-password-required.

If you need to pass additional command-line flags to movemail, set the variable rmail-movemail-flags a list of the flags you wish to use. Do not use this variable to pass the ‘-p’ flag to preserve your inbox contents; use rmail-preserve-inbox instead.

The movemail program installed at your site may support Kerberos authentication. If it is supported, it is used by default whenever you attempt to retrieve POP mail when rmail-pop-password and rmail-pop-password-required are unset.

Some POP servers store messages in reverse order. If your server does this, and you would rather read your mail in the order in which it was received, you can tell movemail to reverse the order of downloaded messages by adding the ‘-r’ flag to rmail-movemail-flags.

Mailutils movemail supports TLS encryption. If you wish to use it, add the ‘--tls’ flag to rmail-movemail-flags.