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