I understand that VERP allows you to encode the recipient's email address into the sending email address and we can use this to identify the recipient in bounce management system.
But if I instead want to use a unique identifier to identify a specific message rather than an email address which I may have sent multiple messages to is there anything wrong with me using a from address of something like
123456789 is my unique message identifier)?
Does using the VERP method offer any other benefits (for example, do mail servers do something differently if the VERP method is used)?
If I send bulk messages (tens of thousands or more) will receiving mail servers have a problem with a unique from address?
I also plan to set the reply-to address to
email@example.com so I can treat human replies differently. Is there likely to be any problems with this? I understand that technically some receiving mail servers may send bounces to the reply-to address, but is this likely to happen in the real world? And are any human replies likely to go to the from (bounce) address if a reply-to is present?
Presumably auto responders will go to the reply-to address too?