Red Hat Summit1.8. Enabling server-side email filtering by using Sieve on a Dovecot IMAP server
You can upload Sieve scripts to a server using the ManageSieve protocol. Sieve scripts define rules and actions that a server should validate and perform on incoming emails. For example, users can use Sieve to forward emails from a specific sender, and administrators can create a global filter to move mails flagged by a spam filter into a separate IMAP folder.
The ManageSieve plugin adds support for Sieve scripts and the ManageSieve protocol to a Dovecot IMAP server.
Use only clients that support using the ManageSieve protocol over TLS connections. Disabling TLS for this protocol causes clients to send credentials in plain text over the network.
Prerequisites
- Dovecot is configured and provides IMAP mailboxes.
- TLS encryption is configured in Dovecot.
- The mail clients support the ManageSieve protocol over TLS connections.
Procedure
Install the
dovecot-pigeonholepackage:# dnf install dovecot-pigeonholeUncomment the following line in
/etc/dovecot/conf.d/20-managesieve.confto enable thesieveprotocol:protocols = $protocols sieveThis setting activates Sieve in addition to the other protocols that are already enabled.
Open the ManageSieve port in
firewalld:# firewall-cmd --permanent --add-service=managesieve # firewall-cmd --reloadReload Dovecot:
# systemctl reload dovecot
Verification
Use a client and upload a Sieve script. Use the following connection settings:
- Port: 4190
- Connection security: SSL/TLS
- Authentication method: PLAIN
- Send an email to the user who has the Sieve script uploaded. If the email matches the rules in the script, verify that the server performs the defined actions.
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