Email Server LANMailServer

LANMailServer needs to store files, such as emails sent to the LANMailServer SMTP server or all saved emails of configured users.

The System user and Administrators must have full access to the folder; users must be able to read/execute, write, modify, and view folder contents. Permissions for the user can be removed if you always run the LANMailServer Console as an administrator.

Changing the data folder (for experts only!)

The data folder should never be changed; if you do so, it is at your own risk!

NEVER place the data folder on a network drive, removable media, cloud drive, or NAS storage. This can lead to database corruption in the event of connection issues. The database CANNOT be repaired.

Create a new data folder on a local hard drive. The System user and Administrators must have full access to the folder; users must be able to read/execute, write, modify, and view folder contents. Permissions for the user can be removed if you always run the LANMailServer Console as an administrator.

Stop the LANMailServer service through Control Panel - Administration - Services.

Copy all files from the current data folder, typically C:\ProgramData\LANMailServer, to the new data folder.

Start regedit, navigate to

Computer\HKEY_LOCAL_MACHINE\ SOFTWARE\LANMailServer

Change the string DataPath to the name of the new folder.

For 64-bit systems, navigate to

Computer\HKEY_LOCAL_MACHINE\ SOFTWARE\WOW6432Node\LANMailServer

Also change the string DataPath to the name of the new folder here.

Restart the service.

Errors can be found in the Windows Event Log or in the file LMLog.txt in the new data folder.

Stores the SQLite database with email data in the data folder; this is the default setting.
The SQLite database stores the essential data of an email and emails up to 100KB. Larger emails are compressed in the data folder.

For many local email accounts and/or a high volume of email access and email sending, using MySQL is recommended, as SQLite usage can lead to significant delays or error messages.

Using a MySQL database

Stores data in a MySQL database; MySQL 8.0 or MariaDB 10.2 or later with utf8mb4_general_ci encoding is required. Older MySQL/MariaDB versions are not supported as SQL Window functions are used by LANMailServer.
The MySQL database should be installed on the same computer as LANMailServer to avoid delays (network latency). Only the essential data of an email is stored in the MySQL database; the email itself is compressed in the data folder.

Note:
The data in the SQLite and MySQL databases is not retained when switching storage methods. These cannot be exported or imported either, as the table structure and stored data differ.

Install MySQL server yourself

e.g., mydomain.de

LANMailServer checks all emails sent via LANMailServer SMTP against this domain name. If a local email account exists for this domain name and the local part of the email address (before the @), the email will not be sent to the internet but directly imported into the local email account.

e.g.,
mydomain.com
mydomain.eu
mydomain.co.uk

LANMailServer checks all emails sent via LANMailServer SMTP against these domain names. If a local email account exists for one of the domain names and the local part of the email address (before the @), the email will not be sent to the internet but directly imported into the local email account.

Checking external email accounts is only performed if LANMailServer has detected an internet connection. The internet connection type must be set to "Connection via LAN/permanent line/DSL via router."

See also

Configure local email accounts

Note: Emails in external mailboxes are only deleted if this email account is regularly accessed.

Use this setting if you have a permanent internet connection.

Offline mode, do not establish an internet connection

Never establishes an internet connection. All emails in the outgoing queue will never be sent.

Important Note

The type of internet connection affects the LANMailServer SMTP server. The SMTP server only attempts to send emails when you are online. If there is no connection, the SMTP server writes the data to a file (queue) on your hard drive and sends it once you are online.

Specify port -1 to not run a POP3 server secured via SSL.

See also: Notes on SSL access

Possible settings:

Specify port -1 to not run an IMAP4 server secured via SSL.

See also: Notes on SSL access

This value indicates the maximum size of an email that can be added to a folder (mailbox) via an IMAP APPEND command from a client program. Enter a value of 0 to prohibit adding emails.

When emails are sent via SMTP, the email program uses the IMAP APPEND command to store the sent email in the "Sent Items" folder. If the email exceeds the size limit, the email program may completely refuse to send the email.

Possible settings:

If authentication is not required (i.e., anyone can send emails), deactivate this option and choose the not-recommended option "Open Relay."

Important

• Email sending without authentication poses a security risk, as any program, including viruses and worms, could send emails.
• Email archiving is not performed when emails are sent without authentication, as the local email account is unknown in such cases.

Choose the variant "SMTP Auth. Always Necessary for Internet Sending, Not Necessary Locally" to allow emails to be sent to local email accounts without authentication. Emails sent to the internet (non-local email addresses) can only be sent with authentication. This option must be used if LANMailServer is to accept emails directly from the internet via SMTP (Port 25).

See also: Notes on SSL Access

If this function is disabled, emails sent through the LANMailServer SMTP server will be sorted into the respective local account if the email recipient is a local email account.

Enable this function to send the email to the internet even if the recipient has a local email account. The email will also be saved in the local email account; LANMailServer will not retrieve the email again from the external mailbox. To access the external account, IMAP4 should be used, so LANMailServer can more easily filter emails that are already stored in the local email account. When accessing via POP3, the entire email is retrieved from the external mailbox and discarded after verification.

Possible settings:

Using the LANMailServer SMTP server is only possible for security reasons if the username and password of the local email account are specified in the email program under the option "Server Requires Authentication."

This setting is only recommended if you have a permanent internet connection. If using a dial-up connection, there may be issues with email sending as some servers prohibit receiving emails with an IP address from a dial-up connection or immediately mark them as spam or delete them.

Use "Modern Authentication" OAuth2 instead of BASIC/Standard Authentication for mailbox access or email sending

LANMailServeronly supports email providers with SMTP authentication or OAuth2 for security reasons.

Optional Specification: "Optional, Always Overwrite Sender Email Address with This Email Address"

Enter a valid email address to use only this email address as the sender email address for every email sent to the internet. This makes it possible to use a different domain locally than the internet domain.

Placeholder %localpart%: Use the placeholder %localpart% to overwrite the local username of the LANMailServer user for the local part of the email address (before the @), e.g., max@mustermann.de as the sender email address should be overwritten with %localhost%@musterfrau.de, so the sender email address of the outgoing email will be max@musterfrau.de.

Note: If a separate SMTP server is defined in the user's local email account, this SMTP server will always be used for sending emails to the internet.

DomainKeys on Wikipedia

e.g.,

If an email needs to be sent to 250 recipients as CCs and the external SMTP server has a limit of 2 recipients per email, LANMailServer will split the email into 125 individual emails, each with 2 recipients, and send them to the external SMTP server.

This setting can also be used to bypass the GoogleMail error "451-4.3.0 Multiple destination domains per transaction is unsupported." Specify a limit of 1 in such cases. Emails with recipients in different destination domains will be individually sent to the GoogleMail server.

Enable this setting to regularly check a folder for .eml files. The included .eml files will be loaded and either distributed locally or sent to the internet. Sending occurs without confirmation or prior warning.

Notes:

• The LANMailServer service must have read and write permissions for this folder.
• Only .eml files in this folder will be searched, loaded, sent, and deleted; all other files remain untouched.
• The .eml files must be properly formatted and encoded, e.g., they can be created using Thunderbird.
• For security reasons, access to this folder should be restricted to prevent malicious software from placing .eml files there.

The email limit applies separately for each configured local user.

Sender and Subject of the Email
LANMailServer composes a character string from the sender (name and email address) and the subject of the email and sends this via SMS.

Sender, Subject, and Start of the Email
LANMailServer composes a character string from the sender (name and email address), the subject of the email, and the text of the email and sends this via SMS.

Note: This setting should be disabled if not used, as the log files will eventually consume the entire hard drive storage space.

Notes on SSL Access

Guide: Create Custom Self-Signed Certificate with OpenSSL

Notes on SSL Access

JSON API Notes:

• Only HTTP POST calls with the header entry APIkey: <API Key> are accepted; all other calls are rejected with an error.
• Calls must contain valid JSON code with UTF-8 encoding. Incorrectly encoded calls are rejected with a 406 error.
• Examples can be found in the LANMailServer program folder: file api_sample.php as a PHP variant, APISample.dpr as a Delphi variant.

OAuth2 Notes:

• All OAuth2 calls are interpreted based on the directory specification /oauth2/.
• For each local user, you can create OAuth2 clients and access areas.
• The email program must support OAuth2 authentication to be fully configurable.

Notes:

• The email server's SSL certificate is used as the SSL certificate.
• If the HTTP server should not support HTTPS, specify port -1.

You can generate a new API key. After saving, you must update the API key in all custom scripts and programs.

Use get_user to retrieve the stored data and field names. When updating the user, the field names must be used with the same spelling. The password cannot be changed via API.

All characters must be transmitted as UTF-8 encoded.

Pay attention to the StreamMaxLength setting in the clamd.conf file; the size specified here must not exceed StreamMaxLength.

X-Virus-Scanned: ClamWin

to each scanned email. In your email program, e.g., Thunderbird, you can view the email headers to determine if the email was scanned.