Hi Everyone
I have recently deployed a new EFAv4 server to replace my v3. I got caught with the Automatic Recipient Verification feature though, and it took me a few hours to find the issue, so we rejected a heap of email.
When I looked further into it, I discovered that the only "Invalid Recipient" rejection messages were the ones where the destination mailbox was on a cpanel server. None of the of the Exchange server mailboxes experienced this issue.
Which leads me to my question, what could need to be done to a cpanel server running exim that could create the rejections?
As far as I understand, the verification check is a partial SMTP transaction to determine if the user is valid. My thinking is that this 'feature' could be considered an information leak from a mail server and maybe cpanel has some sort of protection against this? Of course, cpanel support is not what this forum is for, but I am wondering if anyone has any insights here that may be useful. I would like to have the recipient verification switch on if I can make it work.
Matthew