@FIPS to the rescue.
My website went down. Looks like my provider's firewall nuked all inbound IPv4 TCP/ICMP to my server — no SSH, no HTTP, no ping. tcpdump on the box showed zero packets arriving on those ports.
I decided to check FIPS, and sure enough, it was up and I could connect! FIPS slipped through on a UDP tunnel port the filter wasn't blocking, so my agent SSH'd in over the npub…fips address and diagnosed the whole thing from inside while clearnet was dead.
Pretty cool.