Complete Virtual Mail Server/POP3
This article is part of the Complete Virtual Mail Server series, and may require previous parts to have been read or followed.
This guide will configure a mail server to use POP3 instead of IMAP.
POP3 is an old protocol without many features that are considered vital for modern mail systems. It is HEAVILY DISCOURAGED to use POP3. By proceeding, please make sure to fully understand the consequences of this choice.
POP3 and IMAP can NOT coexist on one server without the threat of losing mail. Many POP3 clients delete mail after downloading it by default, which interferes with the operation of IMAP. Please choose one of them.
Courier-IMAP to Database
Please follow Complete_Virtual_Mail_Server/Courier-IMAP_to_Database until arriving at sections "Configuring/Testing IMAP". These should be substituted with the following sections.
POP3 requires little configuring to get working. It is however recommended to skip this section and not enable/use pop3 and thus leave this setting at 'NO: a user may unwittingly remove all messages that were supposed to be stored on the server for imap usage, then incorrectly configure their mail client and purge the server of their mailbox if configured this way!
##NAME: POP3DSTART:0 POP3DSTART=YES
Courier-pop3d should be started:
Once started, telnet could be used to identify initial problems. Once logging in with telnet works, a mail client can be used:
telnet foo.example.com 110
+OK Hello there. user testuser +OK Password required Pass secret +OK logged in
This is the first time the password is used in plain text. It was previously only known as $1$16117118$ajxN3QRilmP5zLVHjTkE31.
Remember to prepare the user maildir with the courier-maildirmake tool.
If testing works properly, add courier-pop3d to the default runlevel:
rc-update add courier-pop3d default
##NAME: POP3DSSLSTART:0 POP3DSSLSTART=YES ##NAME: TLS_CERTFILE:0 TLS_CERTFILE=/etc/ssl/courier-imap/foo.example.com.pem
Starting this server should allow pop3 to work through SSL: