In contrast to the Postfix server, IMAP and POP3 servers do not run permanently as independent daemons but are started up for the associated connection by the inetd daemon at connection setup. There is thus one dedicated IMAP or POP3 daemon per IMAP and POP3 connection. In the event of heavy parallel use this can result in considerable demands on resources.
To permit the inetd daemon to start the individual IMAP and POP3 daemons, the inetd daemon must be configured appropriately. In the standard case the inetd daemon is configured automatically during IMAP installation.
If problems should occur when you are operating IMAP or POP3 servers, you should proceed in accordance with the description below to check whether the inetd daemon has been configured correctly:
| In the /etc/inet/services file check the entries which assign the service names to the port numbers of the IMAP and POP3 services. The following entries are required: pop-3 110/tcp # Post Office V3 pop-3s 995/tcp # TLS secured Post Office V3 imap 143/tcp # IMAP imaps 993/tcp # TLS secured IMAP |
| Ensure that a symbolic link exists from In the inetd configuration file /etc/inet/inetd.conf check the entries for the individual service names. The following entries are required: pop-3 stream tcp nowait SYSROOT /usr/sbin/in.ipop3d in.ipop3d pop-3s stream tcp nowait SYSROOT /usr/sbin/in.ipop3d in.ipop3d imap stream tcp nowait SYSROOT /usr/sbin/in.imapd in.imapd imaps stream tcp nowait SYSROOT /usr/sbin/in.imapd in.imapd |
| If you have modified the inetd configuration file /etc/inet/inetd.conf
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IMAP and POP3 servers have no configuration file of their own. Furthermore, IMAP and POP3 servers only support the standard Mbox format for the user mailboxes, but not the Maildir format supported as an alternative by the Postfix server.