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Note: This is pre-release documentation.
Please access https://doc.dovecotpro.com/latest/ for documentation on released versions.
Dovecot contains various configurable and built-in resource limits designed to prevent denial of service situations. This page lists those limits.
⚠️ TODO
This list is currently incomplete.
quota_mail_size| Default | unlimited |
|---|---|
| Value | size |
| See Also |
The maximum message size that is allowed to be saved (e.g. by LMTP, IMAP
APPEND or doveadm save). If configured, will also be advertized with
APPENDLIMIT extensions for IMAP clients, and SIZE extension for LMTP clients.
quota_mailbox_count| Default | unlimited |
|---|---|
| Value | unsigned integer |
| See Also | |
| Changes |
|
Maximum number of mailboxes that can be created. Each namespace is tracked separately, so e.g. shared mailboxes aren't counted towards the user's own limit.
quota_mailbox_message_count| Default | unlimited |
|---|---|
| Value | unsigned integer |
| Changes |
|
Maximum number of messages that can be created in a single mailbox.
quota_message_count| Default | unlimited |
|---|---|
| Value | unsigned integer |
| See Also |
Maximum number of messages for the Quota Root. This value is still
multiplied by quota_message_percentage to get the final value
(in this mailbox or namespace). This is reported as the MESSAGE limit in IMAP
GETQUOTA commands. Using 0 as the value means the same as unlimited.
quota_storage_size| Default | unlimited |
|---|---|
| Value | size |
| See Also |
Quota storage size limit for the Quota Root. This value is still
multiplied by quota_storage_percentage and then increased by
quota_storage_extra to get the final value (in this mailbox or
namespace). This is reported as the STORAGE limit in IMAP GETQUOTA commands.
Using 0 as the value means the same as unlimited.
lmtp_user_concurrency_limit| Default | 10 |
|---|---|
| Value | unsigned integer |
| Changes |
|
Limit the number of concurrent deliveries to a single user to this maximum value.
It is useful if one user is receiving numerous mail messages and thereby causing delays to other deliveries.
To prevent limiting concurrent user deliveries set this to unlimited.
mail_max_userip_connections| Default | 10 |
|---|---|
| Value | unsigned integer |
The maximum number of IMAP connections allowed for a user from each IP address.
This setting is checked only by backends, not proxies.
Note that for this to work, any username changes must be done already by passdb lookup (not by userdb lookup).
Unique users are identified via case-sensitive comparison.
There is a 10 MB limit for a single message header block, and a 50 MB limit for all header blocks in a message.
Maximum number of MIME parts per message is 10000. A maximum of 100 MIME parts can be nested in the same hierarchy path.