Synchronet v3.19b-Win32 (install) has been released (Jan-2022).

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Relay Outgoing SMTP Mail through Vertrauen

Your ISP restricts or blocks outbound connections to TCP port 25 so you are unable to have the Synchronet Mail Server perform Direct Delivery of email messages to public mail (SMTP) servers which require mail delivery on TCP port 25.

Some public mail services (e.g Gmail) reject email messages from your server due to a blocked/untrusted IP address or lack of a “SPF TXT” DNS record that authorizes mail to be sent from your mail server for your hostname.

Use Vertrauen's Synchronet Mail Server (on TCP port 587) to relay your outbound Internet mail.


  1. If you do not already have a QWK networking account on Vertrauen, create one.
  2. If running Synchronet Control Panel for Windows, shut it down.
  3. Add RELAY_TX and RELAY_AUTH_PLAIN to the Options key value in the [mail] section of your ctrl/sbbs.ini file. Example: Options = ALLOW_POP3 | RELAY_TX | RELAY_AUTH_PLAIN
  4. Edit the following keys in the [mail] section of your ctrl/sbbs.ini file:
RelayUsername=your BBS's QWK-ID
RelayPassword=your QWKnet account password

Alternatively, if you using Synchronet Control Panel for Windows, you can use the SBBSCTRL:Mail->Configure menu option to make the configuration changes and then hit the 'OK' button:

Synchronet Mail Server configuration for relaying through Vertrauen

Note: the “Use Relay Server” radio button must be checked on the “SendMail” tab for the “Relay” tab shown above to appear in the configuration dialog box.

Or... in SCFG v3.20+, in Servers->Mail Server->SendMail Thread...

║                 SendMail Thread                 ║
║ │Enabled                       Yes              ║
║ │Rescan Interval               1 hour           ║
║ │Connect Timeout               10 seconds       ║
║ │Auto-exempt Recipients        Yes              ║
║ │Max Delivery Attempts         50               ║
║ │Delivery Method               Relay            ║
║ │Relay Server Address ║
║ │Relay Server TCP Port         25               ║
║ │Relay Server Authentication   Plain            ║
║ │Relay Server Username         your-qwk-id      ║
║ │Relay Server Password         pass             ║

This relay service can be terminated for one or all clients for any reason at any time. Most notably, if you send SPAM through Vertrauen, you will lose all access to Vertrauen's services, including this one. Your relayed mail messages are not private and there cannot be any expectation of privacy.

See Also