A method for establishing a single identity on a cloud computing platform, comprising: validating a user credential associated with a computer; receiving an identification of a domain for which the single identity is to be established from the computer; in response to validating the user credential, configuring a directory service on the cloud computing platform for sign-ons from users of the domain, wherein said configuring comprises: determining that the domain is a public domain; in response to determining that the domain is a public domain, sending data to the computer, said data comprising a user identifier, UID, which has a unique value among UIDs on the cloud computing platform and which is associated with the user credential provided by the computer; determining that the data is accessible at a known location in the domain, wherein said known, public location on the domain is a mail exchanger, MX, record, or a domain TXT, text, record on the domain; determining to permit a log in to a second computer of the domain in response to determining that the directory service authorizes a credential associated with the log in; and authorizing the credential associated with the log in to access a software service provided on the cloud computing platform in response to determining that the directory service authorized the credential associated with the log in. validating a user credential associated with a computer; receiving an identification of a domain for which the single identity is to be established from the computer; in response to validating the user credential, configuring a directory service on the cloud computing platform for sign-ons from users of the domain, wherein said configuring comprises: determining that the domain is a public domain; in response to determining that the domain is a public domain, sending data to the computer, said data comprising a user identifier, UID, which has a unique value among UIDs on the cloud computing platform and which is associated with the user credential provided by the computer; determining that the data is accessible at a known location in the domain, wherein said known, public location on the domain is a mail exchanger, MX, record, or a domain TXT, text, record on the domain; determining that the domain is a public domain; in response to determining that the domain is a public domain, sending data to the computer, said data comprising a user identifier, UID, which has a unique value among UIDs on the cloud computing platform and which is associated with the user credential provided by the computer; determining that the data is accessible at a known location in the domain, wherein said known, public location on the domain is a mail exchanger, MX, record, or a domain TXT, text, record on the domain; determining to permit a log in to a second computer of the domain in response to determining that the directory service authorizes a credential associated with the log in; and authorizing the credential associated with the log in to access a software service provided on the cloud computing platform in response to determining that the directory service authorized the credential associated with the log in.