One of my biggest obstacles with being a web hosting company is when a client assumes our mailserver is down when it's not. For instance, I'll get one client out of hundreds that is having problems with connecting and he assumes it's my mailserver even though the other hundreds of clients are able to send/recieve just fine. Is there something out there that I can send these clients to prove that the mail server is healthy. Like an authenticated source with a datestamp and shows that all dns and mx records are fine etc..
I know about the hosttracker type sites, but that just shows whether the main server is online, not the mailserver part.
It would be nice to just go to this site and run the test and send them the link and tell them the next necessary steps. Because they get nasty sometimes assuming it's our fault.