A Google Webmaster Help thread has a couple webmasters concerned that Google is reporting specific IP addresses in the Webmaster Tools reports, as opposed to the domain associated with the IP address.

This is actually not too uncommon. Heck, I see some in my reports:

But the concern for this webmaster is that the top to links to his site come from his domain and his IP address. I guess he is concerned of a duplicate content issue or Google not recognizing his domain name properly.

Google’s JohnMu told them not to worry. He said:

Do you agree? Is this something a webmaster should not worry about?

Forum discussion at Google Webmaster Help.