Strange url....?

Question

Domain Name System

Explain why ac
opens, I understand it is somehow connected with the .ac zone, but why don't other zones open like that?

Answer 1

.ac has an A-record, as opposed to eg. .ru zones. .io, by the way, also has an A-record. Perhaps because they are relatively fresh. Why this is done - one can only guess.
# dig ac
; <<>> DiG 9.3.1 <<>> ac
;; global options: print cmd
;; got answer:
;; ->>HEADER<< - opcode: QUERY, status: NOERROR, id: 58178
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 7, ADDITIONAL: 0
;; QUESTION SECTION:
;ac. IN A
;; ANSWER SECTION:
ac. 85584 IN A 193.223.78.210
;; AUTHORITY SECTION:
ac. 85584 IN NS b.ns13.net.
ac. 85584 IN NS b.nic.io.
ac. 85584 IN NS b.nic.ac.
ac. 85584 IN NS a.nic.ac.
ac. 85584 IN NS ns3.icb.co.uk.
ac. 85584 IN NS ns1.communitydns.net.
ac. 85584 IN NS a.ns13.net.

Answer 2

Because for ac. there is a type A domain record pointing to a server that responds via http (perhaps even contains records about the corresponding virtual host)
There is nothing special about this.

Answer 3

this has nothing to do with the ".ac" zone, it is your browser that kindly starts sorting out suffixes, starting with ".com"

Answer 4

Thanks, Mozilla is self-willed.
but usually it shows the real address that was picked up, and here I even have links within the site that link to this AC.