## MailFront

# POP3 Front End

The POP3 front end is composed of two pieces: an authentication front end and a transfer back-end.

Connections are timed out after `$TIMEOUT` seconds of inactivity (defaults to 1200 seconds or 20 minutes), or `$SESSION_TIMEOUT` seconds after the connection was established (defaults to 86400 seconds or 24 hours).

## pop3front-auth

Usage: `pop3front-auth CVM PROGRAM [ ARGS ... ]`

`pop3front-auth` authenticates the username and password sent by the client using the named CVM. If successful, it sets up the environment and executes `PROGRAM`. It also offers RFC 1734 complient AUTH support through cvm-sasl.

If `$AUTH_TIMEOUT` or `$AUTH_SESSION_TIMEOUT` are set, they override `$TIMEOUT` and `$SESSION_TIMEOUT` respectively.

If `$MAXUSERCMD` is set, no more than the specified number of the `USER` command may be issued. If `$MAXAUTHFAIL` is set, no more than the specified number of authentication failures may occur. After these limits are reached, the client is disconnected.

## pop3front-maildir

Usage: `pop3front-maildir [ DEFAULT-MAILDIR ]`

`pop3front-maildir` serves messages via POP3 out of a maildir. If `$MAILBOX` is set, its contents are used as the path to the mailbox, otherwise the `DEFAULT-MAILDIR` argument must be present. If `$MAX_MESSAGES` is set, the total number of accessable messages will be limited to that number. In addition, if either of `$MAX_CUR_MESSAGES` or `$MAX_NEW_MESSAGES` are set, the total number of accessable messages in the `cur` and `new` subdirectories respectively will each be limited to that number.

If the filenames in the maildir contain a size indicator, as specified here for Courier IMAP and here for Dovecot, this program will avoid using stat to calculate the file size. This is a significant performance optimization on systems with either very large or very many mailboxes.