POP3 SASL SASL AUTH OAUTH2 SASL-IR RFC1734 RFC5034 RFC6749 RFC7628 # # Server-side AUTH OAUTHBEARER REPLY AUTH +OK Login successful From: me@somewhere To: fake@nowhere body -- yours sincerely # # Client-side pop3 POP3 OAuth 2.0 (OAUTHBEARER) authentication with initial response pop3://%HOSTIP:%POP3PORT/888 -u user --oauth2-bearer mF_9.B5f-4.1JqM --sasl-ir # # Verify data after the test has been "shot" CAPA AUTH OAUTHBEARER %b64[n,a=user,%01host=127.0.0.1%01port=%POP3PORT%01auth=Bearer mF_9.B5f-4.1JqM%01%01]b64% RETR 888 QUIT