A DNS attack, just two days before Christmas, has spoiled the holiday shopping plans of many of the online shoppers. Shoppers were unable to access several leading web sites including Amazon. com and Wal-Mart. com.

Nuestar, which provides DNS facilities under the brand name of UltraDNS, revealed that its San Jose and Palo Alto services got affected and the effect was just in California. The effect was due to DDoS attack which happened around 12:45 AM Thursday, GMT and company identified it as abnormal fluctuation of queries.

Other affected websites include Salesforce. com and Linden Labs. Though Amazon and other e-commerce sites were out of order only for about an hour, customers feel that the incident was unfortunate and made them lose out on some good deals.

In a message, Jeff Barr of Amazon Web Services wrote that temporary suspension of online shopping services in US West Coast also took down S3 and EC2 in many places.

NeuStar identified the problem as soon as it started erupting, and taking control over the situation, it also started communicating the guide lines to its customers.