A method wherein a first user obtains an identifier for a desired destination user, makes a request to a server for a data communication with that desired destination user, retrieves a computer network address from a directory entry for that desired destination user, retrieves the source computer network address from the request packet from the first user, and sends requests to the computers of both users for return of respective stored unique identifiers. When these respective unique identifiers are received at the server, a check is made to see that they correspond to only one respective entry in a database, and the server then sends a message to one of the computers to make a data call to the other computer. Users register initially and download a helper application which stores the user's respective unique identifier together with, in a preferred embodiment, a unique password, which is also stored in the respective entry in the database. The helper launches a NetMeeting application passes its associated user's names.