Bot
Following the SMTP rules
An old blog post from 2013, that’s still relevant today.
“Blocked for Bot-like Behavior”
An ESP asked about this error message from Hotmail and what to do about it.
“Bot-like” behaviour usually means the sending server is doing something that bots also do. It’s not always that they’re spamming, often it’s a technical issue. But the technical problems make the sending server look like a bot, so the ISP is not taking any chances and they’re going to stop accepting mail from that server.
If you’re an ESP what should you look for when tracking down what the problem is?
First make sure your server isn’t infected with anything and that you’re not running an open relay or proxy. Second, make sure your customers aren’t compromised or have had their accounts hijacked.
Then start looking at your configuration.
HELO/EHLO values
Whirlwind that is M3AAWG
It’s been a great conference, and it’s only about half done. As is common at these conferences, I write down lots of things we should do and need to publish. The difference is now that we are growing I may have the time to put the polish on them and get them published.
Today’s keynote discussed the economics of botnet mitigation. Michel van Eeten from Delft University of Technology presented information compiled from some different datasets about botnets.
Good news
Botnet infection rates are relatively stable. They’ve not spiraled out of control like some people were predicting.
Interesting news
More than 50% of bot infections are contained on 50 ISPs in the entire world.
Bad news
Centers set up specifically to fix botnet infections don’t really have a big impact on infection cure rate.
Good news
ISP actions and walled gardens do have an impact on infection cure rates.
The biggest take away from the session is that ISPs are critical in both protecting from infection and helping users cure infection once it happens.