I have a Vista machine which I connect to regularly, and it no longer works. No config changes have been made in quite some time. The only changes along those lines are regular updates with Windows Update. Every time it pops up, I press Install. It is a legit copy of Vista. This problem started a week ago, after it had been working for months.
I have it set to listen on a non-standard port. If I run TCPView or netstat, I can see it listening on the port I specified. If I telnet to that port from the machine itself, I can start typing away, which proves that TCP connectivity is there.
Now, if I go to another machine on the lan, any other machine, I cannot connect to it. I used netcat on a FreeBSD machine to perform the same test as above, and the connection simply times out. If I run netcat on the Vista machine to open some random port, I can reach that port from the FreeBSD machine without issue, so communication between the two machines is fine.
I do not have any firewalls setup on the Vista machine. There is Windows Defender, but I am never prompted to allow Remote Desktop, and given that one of the main EXEs for Windows does the work, I don't see how Windows Defender could be having an effect on it, or how I would configure it.
I am out of ideas. Why won't Remote Desktop accept incoming connections? I've tried rebooting, of course.