Source : http://www.xeams.com/smtpgateway.htm
Download :
x86 version : http://www.positiv-it.fr/QNAP/APP/SmtpGateway_2.1.0_x86.qpkg.zip
x64 version : http://www.positiv-it.fr/QNAP/APP/SmtpGateway_2.1.0_x86_64.qpkg.zip
Dependency : QJDK8
Note :
credential on first login : admin / letmein
listen on port 5050
About :
Synametrics Smtp Gateway is an SMTP server that can be used for two purposes:
As backup e-mail server - This is done by adding an additional MX record in the DNS server with a lower priority. Sender's e-mail server will try to send messages to your primary server. If that is not available, it will attempt to send it to the Smtp Gateway, which is acting as a backup server. When your primary server comes back up, messages will be delivered to its final destination.
Load balancing for out-bound messages - Users can use the Synametrics Smtp Gateway to send out-bound messages to recipients on the Internet. This elevates significant load from your primary e-mail server, particularly if you need to send out-bound messages to hundreds or thousands of recipients.