3 ms·
A port. RFC 1912 states "Labels may not be all numbers, but may have a leading digit (e.g., 3com.com)."
by otterlicious 6y ago
A port. RFC 1912 states "Labels may not be all numbers, but may have a leading digit (e.g., 3com.com)."
- zeroimpl 6y agoFWIW I had googled whether hostnames may be entirely digits before asking this, and this SO answer suggested yes. Perhaps that doesn’t apply to URLs? But to be clear I meant hostname not a FQDN, because obviously there is no ambiguity once a dot is present. https://serverfault.com/questions/638260/is-it-valid-for-a-hostname-to-start-with-a-digit https://serverfault.com/questions/638260/is-it-valid-for-a-h...