Red Hat ENTERPRISE LINUX 5 - DEPLOYMENT Deployment Manual page 405

header information is downloaded for messages until opened, saving bandwidth. The user also has
the ability to delete messages without viewing or downloading them.
For convenience, IMAP client applications are capable of caching copies of messages locally, so the
user can browse previously read messages when not directly connected to the IMAP server.
IMAP, like POP, is fully compatible with important Internet messaging standards, such as MIME, which
allow for email attachments.
For added security, it is possible to use SSL encryption for client authentication and data transfer
sessions. This can be enabled by using the imaps service, or by using the /usr/sbin/stunnel
Section 24.6.1, "Securing Communication"
program. Refer to
Other free, as well as commercial, IMAP clients and servers are available, many of which extend the
IMAP protocol and provide additional functionality. A comprehensive list can be found online at
www.imap.org/products/longlist.htm.
24.1.2.3. Dovecot
The imap-login and pop3-login daemons which implement the IMAP and POP3 protocols are
included in the dovecot package. The use of IMAP and POP is configured through dovecot; by
default dovecot runs only IMAP. To configure dovecot to use POP:
1. Edit /etc/dovecot.conf to have the line:
protocols = imap imaps pop3 pop3s
2. Make that change operational for the current session by running the command:
/sbin/service dovecot restart
3. Make that change operational after the next reboot by running the command:
chkconfig dovecot on
Please note that dovecot only reports that it started the IMAP server, but also starts the POP3
server.
Unlike SMTP, both of these protocols require connecting clients to authenticate using a username and
password. By default, passwords for both protocols are passed over the network unencrypted.
To configure SSL on dovecot:
• Edit the dovecot configuration file /etc/pki/dovecot/dovecot-openssl.conf as you prefer.
However in a typical installation, this file does not require modification.
• Rename, move or delete the files /etc/pki/dovecot/certs/dovecot.pem and /etc/pki/
dovecot/private/dovecot.pem.
• Execute the /usr/share/doc/dovecot-1.0/examples/mkcert.sh script which creates the
dovecot self signed certificates. The certificates are copied in the /etc/pki/dovecot/certs and
/etc/pki/dovecot/private directories. To implement the changes, restart dovecot (/sbin/
service dovecot restart).
Mail Access Protocols
for more information.
http://
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