I just installad Fedora 22 and DNF (yum's replacement) is performing terrible.
9 out of 10 request fails out of timeout, with random effect specifying IPv4 or not. The problem seems to be that DNF can't pick a proper mirror nad often pick a non-responding one, or a terribly slow one.
Feil: Error downloading packages:
Curl error (6): Couldn't resolve host name for https://mirrors.fedoraproject.org/metalink?repo=updates-released-f22&arch=x86_64 [Could not resolve host: mirrors.fedoraproject.org]
Also, I think IPv6 is caussing some trouble, so it has been deactivated on my system. Restarts dosn't change anything either...