The dscacheutil utility no longer works for OS X 10.10, the new one is
sudo discoveryutil udnsflushcaches
The dscacheutil utility no longer works for OS X 10.10, the new one is
sudo discoveryutil udnsflushcaches
If your network connection (especially ethernet connection) stalling/freezing from time to time, try disabling the new MultiPath TCP (MPTCP).