We have the latest SmarterMail and declude installed. And enabled X-Identify for both incoming and outbound mail:
Any mail host received mail from our host now identified our private IP instead of mail server IP to
run RDNS and SPF check and led the result to fail. ( the server receiving email is also a SmarterMail host). Even they set our mail server ip to IP Bypass won't work. The SmarterMail host will only process sender client IP to check.
But if we sent the email to Gmail, the gmail is able to grep the mail host IP but not sender's private IP. (we fixed DKIM issue last Friday)
Where we and they can check else? We temporarily requested them to set all of our client IPs to IP Bypass. But this is not a solution....Thank you!