[bitfolk] Routing from AWS issue?

The recent WordPress update has reminded me that in the WordPress wiki page (updated with a couple more tips, BTW) I mention the WP Remote service which lets you do things like upgrade WordPress on many sites with a click or two. When it works, it's great, but I am finding it is not always able to communicate with my sites. It wasn't working on Saturday, it was on Sunday, it's not now. At one point, they were using their own server and a single IP address. Now they're using AWS and the IP address varies according to whatever Amazon assign to them at the time. My suspicion was that assorted nasties are also using AWS, behaving badly, triggering a Fail2Ban jail one way or another, and this sometimes leads to WP Remote being caught in the ban when it is assigned the same IP address as the nasties had. The problem with that theory is that if I look at the IP addresses that have been successfully used over the past few months, via looking in the webserver logfiles, there are three: 50.16.139.168 54.224.171.85 54.242.241.26 .. and none of them are currently being blocked by iptables. This is affecting both my VPS. Surprisingly few addresses are being currently being blocked, and none of them look to be anywhere near those, and I can only spot one in common between the two. And that's nothing to do with Amazon. Is anyone else seeing anything similar? Ian