Domain name service provider ZoneEdit was hit with a significant denial of service attack Tuesday, leaving thousands of customers with irregular service over the past two days.

The attack started early Tuesday morning Eastern time and continued through Wednesday, affecting four of ZoneEdit’s 25 domain name servers, says George DeCarlo, senior VP of marketing for Dotster, which owns ZoneEdit. Though less than 5 percent of ZoneEdit’s customer base was affected, DeCarlo says the percentage amounts to thousands of customers.

As of mid-day Wednesday, one of the four servers targeted in the DoS attack made a full recovery. So far, there is no estimate as to when the other machines will be running normally, but DeCarlo says the company is working on it as fast as they can.

There is no indication as to whether there is a connection, ZoneEdit hosted the domain of FastMP3Search.com.ar, an Argentine site that many anti-spyware groups say was one of the world’s worst spyware spreaders.