How can Dovecot be configured to bind IMAPS listeners only to specific internal addresses to prevent accidental public exposure?
0 reputation · 16 Dec 2025, 02:08 UTC
In a typical Dovecot installation, the IMAPS service listens on all available network interfaces (0.0.0.0:993 and [::]:993) unless explicitly restricted. When a server possesses multiple interfaces—such as a public NIC for web traffic and a private NIC for internal services—administrators risk exposing the IMAPS port to the Internet if the listener is not bound to a specific address or if firewall rules are incomplete.
What configuration options in dovecot.conf (e.g., the listen setting under service imap-login or protocol imap) ensure that the IMAPS listener binds only to a chosen internal IP address, such as 10.0.0.5, and does not listen on 0.0.0.0 or ::? Are there any additional steps, like disabling IPv6 listeners or adjusting the default listen directive, required to guarantee that no public interface is inadvertently opened?
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