The command should then be processed by the server normally. If the combination is not valid, the server will return a 502 response. Clients must provide authentication when requested by the server. It is possible that some implementations will accept authentication information at the beginning of a session, but this was not the original intent of the specification. If a client attempts to reauthenticate, the server may return 482 response indicating that the new authentication data is rejected by the server.
All information is passed in cleartext.
If the reverse lookup fails, the IP address, represented in dotted-quad format, will be used. Additionally, the server should log the event, including the email address This will provide a means by which subsequent statistics generation can associate newsgroup references with unique entities - not necessarily by name. General Responses may also be received.