Details DNS is the component that translates names into IP addresses . You don't run DNS yourself, but you must use your ISP's DNS server in order to access the Internet. The hacker is scanning your machine to see if this has happened. Somebody might have misconfigured their machine.
Many people configure their machines by hand.
One of the items they must configure is which DNS server to use. They have misconfigured their machines to point at your system. During the first part of the year 2000, we've seen a dramatic rise in the number of DNS probes. NXT overflow The attack against RedHat 6 Linux that will allow a hacker to break into that system. The reason for the port probe.