Abstract: Detecting illegitimate typosquatting with Internet Protocol (IP) information includes, at a computing device having connectivity to a network, obtaining a list of domains and filtering the list to generate a list of monitored domain strings. IP information is passively determined for domains associated with each of the monitored domain strings. A domain requested in network traffic for the network is identified as a candidate typosquatting domain and the candidate typosquatting domain is determined to be an illegitimate typosquatting domain based at least on the IP information. An action is initiated related to the illegitimate typosquatting domain.