This option is useful when SynaMan is integrated with Xeams or you want only to process in coming emails from the Internet. You should NOT use this option if you want to use the Embedded SMTP server for inbound as well as outbound emails, if you're not using Xeams.

Using this option will cause SynaMan to perform an MX Lookup on the recipient's domain and messages will be automatically routed to the available server according the the MX priority. Therefore, use this option if you want to use SynaMan for inbound as well as outbound messages.

MX Lookup on LAN

It is very common to place SynaMan in between your spam filter and the corporate email server where IP addresses are NATed behind a firewall. The following image depicts such network design.

In this case, emails coming from the Internet needs to be forwarded to your corporate email server (MS Exchange in this example). Similarly, outbound emails needs to be forwarded to the Spam Filter.

Performing an MX Lookup within SynaMan will result in an incorrect result. Therefore, use the following method to bypass MX Lookups:

• Open Windows File Manager Windows or an SSH session if you're using Linux on the machine where SynaMan is running.
• Go to $INSTALL_DIR\config folder. $INSTALL_DIR refers the folder where SynaMan is installed.
• Create a new file called hosts.txt
• Add the following lines

  your.company.com	192.168.1.20
  ALLDOMAINS              192.168.1.5

• By adding hosts.txt file you're telling SynaMan to send every email with recipients belong to your company's domain to MS Exchange. Similarly, every other domain should be sent to your spam filter, which is typically the case for outbound emails.