When URL’s are just not resolving the way you want it, time to clear or “flush” the dns nameserver local cache.

How to clear the local DNS cache? Open terminal and type the following command for your appropriate OS X Version:

Note: Updated on December 25, 2016:

macOS 10.12

sudo dscacheutil –flushcache; sudo killall –HUP mDNSResponder

OS X 10.11

sudo dscacheutil -flushcache; sudo killall -HUP mDNSResponder

OS X 10.10

sudo discoveryutil udnsflushcaches

OS X 10.9

dscacheutil -flushcache; sudo killall -HUP mDNSResponder

OS X 10.7 & 10.8

sudo killall -HUP mDNSResponder

OS X 10.5 & 10.6

sudo dscacheutil -flushcache

You may need to enter your password.

Are you a Windows or Linux user? No problem, here’s some love:

Windows

ipconfig /flushdns

Linux (Depending on your distro)

/etc/init.d/named restart
/etc/init.d/nscd restart