> In our terms botnet can be a mix of a free and paid Mailgun accounts. Botnets can include anything from 2-3 to dozens and hundreds of accounts created at diff

> In our terms botnet can be a mix of a free and paid Mailgun accounts. Botnets can include anything from 2-3 to dozens and hundreds of accounts created at different time and using different billing plans. My criticism is I've never heard of a botnet referred to as a group of accounts. To me, a botnet is a group of host computers that run some sort of proxy server (tens of thousands of hosts). I've never given thought to what someone would call a group of email accounts aimed at exploiting a service, but to me botnet seems like it would be specific to a network of computers, sometimes compromised, sometimes not, running a type of proxy or automated software. > We are talking about Mailgun service - the time they need to invest in building some solution on top of Mailgun that pays back is just not worth it. The problem is when it comes to a service like yours, if it really is that hard to bulk mail, then the guys using your service aren't the guys getting a 1 in 125m response rate. Anyone sending that kind of volume would assume their messages were going to a spam folder, and sending larger volumes to compensate for it. Someone going through the hoops you set in place, are doing it because your service gets inbox. This means they can send bulk email to higher quality lists, and their response rate will be significantly higher than 1 in 125m, more like 1% to 2% response rates. In this case, the people actually sending mail through your service probably don't even bother making those accounts themselves. They likely find people who specialize in circumventing your security measures, and pay a premium of $x to $xx per 1,000 accounts. > On the other hand, phishing attacks are very dangerous and this is our biggest threat - we've noticed that they get very high quality lists with 0 bounces, so it might be real bank users and build pages for every atack. This too, but don't forget about simply cracking passwords for the accounts. Simple math. Take the top 100 most used passwords, assume your users are just as naive as most the internet, and you have x% users you can assume will be compromised at some point in the future.