flush opera DNS cache

According to Opera's Senior Developer, Yngve Nysæter Pettersen, the DNS cache in Opera is 10 minutes and there's no means (that he cares to share) to clear it.

That's extremely inconvenient. And my trial and error shows that closing and opening the browser (whole browser, not just tab) successfully cleared the cache immediately.

He's wrong when he says that this is the same on every other browser. This may be true in Chrome as they rip settings every day, but Firefox has network.dnsCacheExpiration with is miliseconds for DNS cache TTL. (This is not documented or shown with the default value when you go to about:config, but still existent.)

@GeorgDangl gives the answer

browser://net-internals/#dns