How quickSMTP stores local messages

Local messages are stored in folder mboxes which is created in the selected work directory.  For each domain that you register with quickSMTP a sub-folder will be created with the name of the domain. Each mailbox will have its folder inside the domain folder.

The structure looks like this:


Each message that a user receives is stored in a separate file with unique name inside her/his account directory. Messages are in MSG format which means that if needed, they can be examined with third-party email clients, such as Microsoft Outlook.

Retention period

For each account you can define retention period in number of days. This period defines how long quickSMTP will store the messages for the specified account. Each message that is past the number of retention days will be erased automatically.

Retention is checked and enforced during housekeeping runs, which are related to queue processing and run right after it.

Please be careful with this functionality, because there is no way to recover messages erased because of exceeded retention period!

Retention policy has two options:

Retention based on arrival time

In this case retention days will be counted from the day on which the message has arrived, regardless if the user has opened it or not. 

Retention based on retrieval time

In this case retention days will be counted from the day on which the user has retrieved the message. As retrieval is considered full download of message (issuing RETR command as per POP3 protocol specifications). 


You can specify quotas on the number of messages or the number of storage space that each account can use. If one of the two quotas is reached, quickSMTP will inform the user by sending her/him a message and will not accept any new messages until the user frees space by erasing messages.

Messages to users will be sent during housekeeping runs, which happen right after queue processing.

Quotas are specified in megabytes e.g. the minimum that you can specify as quota is 1 MB.

quickSMTP news review

Latest Version: 0.3

Important bugfix! There was a bug in version 0.2 that would cause quickSMTP to consume a lot of resources when a client connects to SSL POP3 or SMTP and does not comply with the protocol commands. We recommend you to upgrade

Latest Version: 0.2

Version 0.2 optimizes existing functionality, fixes some bugs and introduces a few new features. Upgrade is highly recommended! 

Version: 0.1

This version is a major upgrade and is not compatible with the previous versions. You need to manually uninstall any previous version before installation!

  • SQLite is being used as back-end storage which means that all .ini files are no longer needed.
  • SSL encrypted POP3 and SMTP protocols are available.
  • New intrusion prevention system that allows you to block nodes who are probing brute force users.
  • Monitoring interface and program that allow you to connect to and monitor your quickSMTP.
  • Statistics with various graphs that can give you a good overview of the operation of your mail server.
  • Quotas for mail storage introduced on per account level.
  • Retention period for local storage of emails.
  • Remote blocking rules have been extended to include expiration time should you need to impose time limited bans.

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