OK, I'm still convinced your ISPs are blocking you.
I believe their algorithm detects what it thinks is a suspicious pattern and then blocks packets that match that pattern. They don't want their customers to be using bots to browse the internet.
By changing the user agent and getting no better results, we show that the problem probably is *not* that "LFS" is on a list of user agents to block. It's more likely a dynamic thing blocking patterns temporarily.
Unfortunately they have too many dodgy customers and so they don't trust you.
In my opinion it is a new thing they have introduced recently to reduce the amount of bot traffic they are facilitating, but unfortunately they are blocking legitimate traffic too.
I can't think of many ways round it. Hopefully the ISPs might change their algorithm to allow perfectly legitimate traffic, but only if they get enough pressure from customers. But from my experience, the main aim of such large companies is to keep taking your money and avoid doing their job if at all possible.
One other possibility is I could remove the whole concept of LFS using http to communicate with our website. It could communicate using custom protocols, in the same way that communications take place with LFS hosts. It's really a big job though, that would take a lot of planning and coding on the web server side.
That may never happen. There is no way I can promise to do that, we have a perfectly good working system that I believe has been broken by the incompetent actions of large ISPs. They have one job - provide you with a proper internet connection - and they are not doing it despite you paying for it every month.
