Aspects of the present invention disclose a method, computer program product, and system for domain name classification. The method includes one or more processors receiving a request for querying a first domain name. The method further includes one or more processors acquiring a first source internet protocol (IP) address and the first domain name from the request. In response to determining the first domain name is not classified, the method further includes one or more processors an access tendency of the first source IP address based on a plurality of classifications of a plurality of domain names queried by the first source IP address. The method further includes one or more processors estimating a first classification of the first domain name based on the access tendency of the first source IP address.