6. DNS Answer Changes during Happy Eyeballs Connection Setup

If, during the course of connection establishment, the DNS answers change by either adding resolved addresses (for example due to DNS push notifications [DNS-PUSH]) or removing previously resolved addresses (for example, due to expiry of the TTL on that DNS record), the client should react based on its current progress.

If an address is removed from the list that already had a connection attempt started, the connection attempt SHOULD NOT be canceled, but rather be allowed to continue. If the removed address had not yet had a connection attempt started, it SHOULD be removed from the list of addresses to try.

If an address is added to the list, it should be sorted into the list of addresses not yet attempted according to the rules above (see Section 4).