Sometime over the weekend, Spark started blocking me from connecting to my home router on port 53.

I used to (it worked on Friday) SSH over port 53 (to get around a work firewall) but back at work this morning it no longer works. I also can't connect from other locations (including another Spark connection) so it appears that they've started blocking port 53.

Anyone else notice this? I've had to change to SSH over port 443 instead.