Apache James : Purely MX record based smtp.

Hello,

I am a bit unclear based on Apache James 3.5.0 docs whether it is able to connect to smtp service provider purely based on MX Records. I have gone through the mailing list historically . I have set the gateway and gatewayPort to published MX Record.

Logs say the following which seem to imply it is still looking for an A Record.

jvm 1 | 30-Jun-2021 10:20:30.654 ERROR [RemoteDelivery-2] org.apache.james.dnsservice.library.MXHostAddressIterator.<init>:79 - Couldn't resolve IP address for discovered host smtpxxx.xxxx.com.

In mailet config  I set up the gateway:


          <!-- A single mail server to deliver all outgoing messages. -->

          <!-- This is useful if this server is a backup or failover machine, -->

          <!-- or if you want all messages to be routed through a particular mail server, -->

          <!-- regardless of the email addresses specified in the message -->

          <!-- -->

          <!-- The gateway element specifies the gateway SMTP server name. -->

          <!-- If your gateway mail server is listening on a port other than 25, -->

          <!-- you can set James to connect to it on that port using the gatewayPort -->

          <!-- element. -->

          <!-- Although normally multiple addresses are implemented through proper -->

          <!-- DNS configuration, the RemoteDelivery mail does allow specifying -->

          <!-- multiple gateway elements, each of which may also have a port -->

          <!-- e.g., mygateway:2525 -->

          <!-- the gatewayPort element is used as a default -->



          <gateway>${env:SMTP_GATEWAY}</gateway>

          <gatewayPort>${env:SMTP_GATEWAYPORT}</gatewayPort>



          <!-- If the gateway requires smtp authentication the following directives -->

          <!-- (gatewayUsername/gatewayPassword) can be used. -->



          <gatewayUsername>${env:SMTP_WEBSSO_USERNAME}</gatewayUsername>

          <gatewayPassword>${env:SMTP_WEBSSO_PASSWORD}</gatewayPassword>


In dnsservice.xml I also enabled


   <!-- Uncomment this if you want James to try a single server for each -->

   <!-- multihomed mx host. -->

   <singleIPperMX>true</singleIPperMX>


Our SMTP service provider is forcing down the MX Record with all A Records being removed.  Is there anything else I need to consider to get this to work ?


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