A system, operable on one or more computers, and a computer-readable media are presented for validating an assertion made by a user that he or she controls a domain name. The system comprises an assertion receiver, authorization code generator, and a validation component. The assertion receiver receives either an explicit or an implicit indication that a particular user exercises control over a domain name. The authorization code generator provides an authorization code, to be electronically published in a Domain Name System (DNS) record associated with the domain name. After the authorization code has been inserted in a DNS record, the validation component accesses the DNS record to determine presence of the authorization code within the DNS records. If the authorization code is present, control of the domain by the user is established.