Mail server stats: 299 connection requests from IP addresses in the bc.googleusercontent.com range in the past 72 hours, 100% of them trying to dump spam/phishing mails, claiming to be from microsoft.com, ubuntu.com, GitHub.com and many more. Google should take note (but it will ignore this, as it has always done).
This is funny, because Google is known to be very rigorous with accepting connections from self hosted mail servers that are often blocked or rejected for, at times, weird reasons. I would expect them to be able to shut down the spammers that use their infrastructure :)