Posts Tagged ‘ipv6 clear dns cache sudo dscacheutil -flushcache’

Don’t forget to flush DNS cache when testing IPv6

March 22nd, 2010 admin No comments

MacOSX resolvers can cache IPv4 addresses, making them preferable to IPv6-capable applications, such as web browsers. The apps are IPv6-capable, but if an IPv4 address is already cached for a given fully qualified domain name (FQDN), the apps can’t look up names properly to prefer IPv6 addresses when available. The fix is to manually clear your MacOSX DNS cache. Do that with the simple command:

sudo dscacheutil -flushcache