A method for evaluating domain names includes storing a listing, for a plurality of non-ASCII Unicode characters, of corresponding ASCII characters that are visually similar to the non-ASCII Unicode characters. A record is received of one or more Internationalized Domain Names (IDNs), each IDN containing at least one of the non-ASCII Unicode characters. The corresponding ASCII characters are substituted for the non-ASCII Unicode characters in the record in order to generate candidate ASCII domain names corresponding to the one or more IDNs. The candidate ASCII domain names are compared to one or more protected ASCII domain names. When a candidate ASCII domain name matches one of the protected ASCII domain names, a protective action is initiated with regard to the IDN corresponding to the candidate ASCII domain name.