How do browsers behave when they receive multiple A-records from dns?

Question

Domain Name System

Subject.
And if there is any behavior if the server does not respond for a long time on this record? What if you sent an error?
Will he try next time to send a request to another ip? Or will he try to send the same request?

Answer 1

Depends on the browser. In general, it is divided into 2 groups:
1) (normal browsers) choose the first IP from the system resolver response (or whatever is in Windows instead) - A-records are usually sent in random order - and go to this IP with an http (s) request. Failed - show error.
2) (very smart) go to the first IP, try to do a TCP handshake. If it doesn't work, go to the next one. And so on until the end. _But_ the next ip is taken only and only if the handshake failed. If the server slows down / timeouts in 60 seconds / responds with a 5/4xx error, then the browser will not go to the next one.