This one had me scratching my head for a while.
I was attempting to access a MySQL database through my home broadband service. The MySQL database had a control panel where remote IP addresses that can access it could be entered. My broadband IP address was there, but I still could not connect to the database.
Checking the error message the database threw back on each connection attempt, it listed a Virgin domain which I did not recognise. Normally the domain that points to a broadband connection includes the IP address in the name, but this one did not.
So pinging that domain, I realise it is *not* my broadband IP address. I add that IP to the list of allowable IPs that can connect to the database, and it immediately lets me in. Very strange.
So what appears to be happening is that when I connect my laptop at home directly to a MySQL database, over the standard port 3306, some kind of proxy at Virgin is catching the connection and making it appear to the end machine like I am in a completely different IP network. I have no idea why they would do this, or how often that IP is going to change.
I’ve noticed there are quite a few recent reports of MySQL connections mysteriously being dropped when using Virgin Cable. I wonder if this proxy has something to do with it?