IPv6 dns resolution on macOS High Sierra

My ISP provides me only with an IPv4 address. After setting up a connection to my university OpenVPN server, I get an IPv6 address. With an example IPv6 address www6.fit.vutbr.cz I can: * host www6.fit.vutbr.cz * ping6 www6.fit.vutbr.cz * traceroute6 www6.fit.vutbr.cz * open http://[2001:67c:1220:809::93e5:916] in a web browser (safari/firefox) BUT, I cannot: * open www6.fit.vutbr.cz in a web browser i.e. web browser does not resolve an ipv6 dns address. If I add the following mapping to /etc/hosts 2001:67c:1220:809::93e5:916 www6.fit.vutbr.cz the web browser finally works. I think it has something to do with scutil --dns showing: DNS configuration resolver #1 search domain : lan nameserver : 192.168.1.1 nameserver : 8.8.8.8 nameserver : 8.8.4.4 flags : Request A records reach : 0x00020002 (Reachable,Directly Reachable Address) I believe, I should see Request AAAA records. Why does host and traceroute6 and ping6 resolve the DNS, but the web browsers don't? Any suggestions? Thanks