A major Distributed Denial of Service in North America last week is being played down by Expedia, one of the sites reported to be affected in the aftermath of the attack.
The problem occurred on Wednesday 23 December when a DDoS hit DNS provider UltraDNS, part of the Neustar brand, causing problems for Amazon, Wal-Mart, Linden Labs and Expedia.
Users across a number of states in the USA were said to be without web services for a number of hours during what was one of the busiest final web shopping days before the Christmas holidays.
Expedia says the attack did not cause any outage for the main Expedia US site, as the attack was directed at its DNS provider UltraDNS.
The wider problem was "not significant", a spokesperson says, but engineers are investigating to evaluate there was change in traffic and bookings around the same time as the attack took place.
For its part Neustar says the DDoS affected services for around an hour only on the West Coast.