Health Check feature in BIND ?

[Mark Andrews]

The real problem is that there are a lot of clients out there that
do not failover to second address in a timely manner.  There is
NOTHING that says you cannot attempt multiple connections at once
or after a short delay.  You do NOT have to wait for connect() to
fail before attempting a second connection.

Clients that implement Happy Eyeballs (RFC 6555) fast fail between
IPv4 and IPv6.  There is no reason not to do this whenever you have
multiple addresses of the same family rather than when you have a
mixture of IPv4 and IPv6 address.

Mark
-- 
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: marka at isc.org