There has been a recurring issue of Korean ISPs blocking Vercel DNS. This open-source project aims to notify you when a domain deployed through Vercel is blocked by ISPs. Vercel DNS ISP Block Watch ...
So an acquaintance is doing an interview and he's asked to write a TCP DNS to DNS over TLS proxy, we're talking about it and he says "well, if you want to try, note that my ISP blocks 1.1.1.1:tcp:853" ...