Okay, this is what is happening - the OTCA domain has been targeted by some foreign IPs in the last couple of years, constantly accessing every page and file, which is creating a massive amount of bandwidth traffic that used to crash the old server every couple weeks before it was moved a few months ago... and all of that data ends up costing me a heap in excess usage charges, despite the Transfan traffic being minimal (and now almost non-existent).

That old server host could only offset some of that bot traffic, while the new server host is taking the approach of shutting down the entire domain to see if it stops the bots, because apparently they have drained the OTCA domain about 100 Gbytes in the month of September (our site only has about 100 Mbytes of data, which would mean each file would need to be accessed over a 1000 times in that time).

In the past, the swarm of guest IPs were from Vietnam, Russia and one IP in America, and I had added them to the IP blocking list on the board... but this time they are all from Huawei in Hong Kong, so I've tried to block them as well, but it might end up blocking legitimate fans in HK from accessing the board, or any of us who go over there and use Huawei for their internet.

It's a no-win situation though, as blocking whole root IPs to prevent the thousands of individual IPs that are probing us, might end up blocking legitimate visitors... and there is already a large number of blocked IPs on our list.
We just have to see what options are left now to stop these thousands of guest bots, as I had hoped that the move of the domain would have fixed this, but it seems that the domain name is the target, not the host.