Network Solutions was attacked last Tuesday and suffered degraded performance on its WorldNIC name servers for about 25 minutes before normal operations were restored, said a spokeswoman for the Herndon, Virginia-based company. She declined to disclose the measures Network Solutions took to mitigate the attack.

Prior to the attack against Network Solutions, the DNS servers at CSL Computer Service Langenbach GmbH, a Dusseldorf, Germany-based company that operates a domain-name registration business called Joker.com, were targeted by what the company described as a "massive" series of denial- of-service attacks.

In an updated advisory that was posted on the Joker.com Web site last Tuesday, CSL and its business partner, EIS AG in Zug, Switzerland, said the attacks were "another order of magnitude than [we] experienced ever before." They began on March 20 and continued to cause interruptions through March 26, the companies said.

Quick action

DNS services were completely interrupted for a short time after the attacks began, according to CSL and EIS. CSL responded by adding more domain-name servers, some of them hosted in external data centers. It also reserved more network bandwidth for Joker.com and set up automated procedures for reacting to unspecified incidents.