Hacker News Reader

Why would this port be blocked?

On public wifis they might not want you to do anything weird, so they block everything except "web ports", i.e. 80,443/tcp

And dns 53/udp otherwise you do not get far.

Sometimes that's blocked too, you're forced to use the local DNS server, which is the only one authorized to access port 53/udp out.

Because nobody needed it for a legitimate reason up to now.