POP3 SASL SASL AUTH EXTERNAL RFC1734 RFC4422 RFC5034 # Server-side AUTH EXTERNAL REPLY AUTH + REPLY %b64[user]b64% +OK Login successful From: me@somewhere To: fake@nowhere body -- yours sincerely # Client-side pop3 POP3 external authentication 'pop3://user;AUTH=EXTERNAL@%HOSTIP:%POP3PORT/%TESTNUMBER' # Verify data after the test has been "shot" CAPA AUTH EXTERNAL %b64[user]b64% RETR %TESTNUMBER QUIT