smtp_server Holds the SMTPServer that spawned this channel.

seen_greeting Holds a string containing the greeting sent by the client in its “HELO”.

received_lines Holds a list of the line strings (decoded using UTF-8) received from the client. The lines have their "\r\n" line ending translated to "\n".

received_data Holds a string containing all of the data sent by the client during the DATA state, up to but not including the terminating "\r\n.\r\n".

rcpttos Holds a list of strings containing the addresses identified in the “RCPT TO:” lines from the client.

peer Holds the name of the client peer as returned by conn.getpeername() where conn is conn.

mailfrom Holds a string containing the address identified in the “MAIL FROM:” line from the client.

fqdn Holds the fully-qualified domain name of the server as returned by socket.getfqdn().

conn Holds the socket object connecting to the client.

addr Holds the address of the client, the second value returned by socket.accept