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Email Settings ​

The Settings page in AdminBolt allows you to configure all backend parameters for Dovecot and LMTP services. Settings are grouped into 11 tabs. Each tab contains fields that can be customized to optimize server performance, authentication, storage, and encryption.

URL: admin/email-settings

1. Authentication ​

Authentication

Configure authentication-related settings for secure mail access.

  • Allow Plaintext Auth – Should be disabled (false) unless you're using TLS. Enabling this without TLS is insecure.
  • Auth Cache Size (MB) – Size of the authentication cache in megabytes. Helps with authentication performance.
  • Auth Cache TTL Failure (sec) – How long (in seconds) a failed authentication attempt stays in the cache.
  • Auth Cache TTL Success (sec) – How long (in seconds) a successful authentication stays in the cache.
  • Auth Max Processes – Maximum number of authentication worker processes.
  • Auth Process Memory Limit (MB) – Memory limit per authentication process, in megabytes.

2. Auto Expunge ​

Auto Expunge

Automatically expunge messages from specific folders.

  • Auto Expunge Spam – If enabled, automatically deletes messages from the Spam folder.
  • Auto Expunge Trash – If enabled, automatically deletes messages from the Trash folder.

3. Compression ​

Compression

Control message compression options.

  • Compress Messages – Enable or disable compression of stored emails.
  • Compression Level – Set the compression level from 1 to 9. Higher values provide better compression but may use more CPU. Default is 6.

4. IMAP Settings ​

IMAP

Configure IMAP service behavior.

  • Idle Check Interval (sec) – Time in seconds for the server to check for new messages during IDLE.
  • IMAP Idle Keepalive Interval (min) – Keepalive interval in minutes for idle connections.
  • IMAP Max Connections per IP – Maximum number of IMAP connections allowed per IP address.
  • IMAP User Limit – Total number of simultaneous IMAP users.
  • IMAP Process Limit – Maximum number of IMAP server processes.
  • IMAP Process Memory Limit (MB) – Memory limit per IMAP process in megabytes.
  • IMAP Service Count (0 = unlimited) – Number of IMAP services that can run concurrently. 0 means unlimited.
  • IMAP Process Min Available – Minimum number of spare IMAP processes to keep available.

5. Quota & IPv6 ​

Quota & IPv6

Manage storage quota enforcement and IPv6 support.

  • Include Trash in Quota – Whether deleted items count against a user's quota.
  • Enable IPv6 – Enable or disable IPv6 support for the mail server.

6. LMTP Settings ​

LMTP

Tune LMTP delivery performance.

  • LMTP Process Limit – Maximum number of LMTP processes.
  • LMTP Process Memory Limit (MB) – Memory limit per LMTP process in megabytes.
  • LMTP User Concurrency Limit – Maximum number of concurrent LMTP deliveries per user.

7. MDBOX Settings ​

MDBOX

Set up mailbox rotation for MDBOX format.

  • MDBOX Rotate Interval (days) – Interval in days to rotate mdbox files. 0 disables rotation.
  • MDBOX Rotate Size (MB) – Maximum file size (in MB) before rotation occurs.

8. POP3 & Postmaster ​

POP3 & Postmaster

Control POP3 access and designate a postmaster contact.

  • POP3 Max Connections per IP – Maximum number of POP3 connections per IP.
  • Postmaster Address – Required field. Sets the contact email address for the domain (e.g., postmaster@example.com).

9. Protocols ​

Protocols

Select which mail protocols are active.

  • Enabled Protocols – Multi-select field where you can choose which protocols to enable (e.g., IMAP, LMTP).

10. SSL/TLS ​

SSL/TLS

Control secure communication settings.

  • SSL Cipher List – Define the list of allowed ciphers for encrypted communication.
  • SSL Min Protocol – Minimum allowed protocol (e.g., TLSv1.2). Older versions (e.g., SSLv3) should be avoided for security reasons.

11. Advanced ​

Advanced

Advanced options related to authentication behavior.

  • Use New Auth Process Per Connection – If enabled, a new authentication process is spawned for each connection.