I recently upgraded to Zimbra 8.7. We provide clients Authenticated SMTP relay, but several have older Outlook apps that are not sending a valid HELO in their connection. In 7.x versions of Zimbra, the mta would fix this on the fly by adding the server's hostname to the end of the client HELO. This has stopped in 8.7 and I have been trying to find a way to enable this behavior.
For example, ESMTP helo=<Art>
would become ESMTP helo=<Art@server.example.com>
so servers with strict HELO rules would not bounce with "Invalid HELO address"
Does anyone know a setting for this in Zimbra/Postfix?
helo=<Art>
appears in the email's headers and some services are rejecting due to this. I't happening for 2 specific clients out of a few thousand that are using the same version of Outlook (2010 version). The previous versions of Zimbra's postfix would automatically correct this behavior, so I was hoping it was a setting I am missing. I know the internals of Zimbra quite well, but this one has got me stumped.