client unix_listen .dovecot-client
c = ./dovecot-auth-cli .dovecot auth username password
client -> VERSION 1 1
client -> SPID 12345
client -> CUID 12345
client -> COOKIE lovelycookie
client -> MECH PLAIN
client -> MECH LOGIN
client -> DONE
client <- VERSION 1 1
client <~ CPID
client <- AUTH 1 PLAIN service=smtp secured no-penalty nologin resp=dXNlcm5hbWUAdXNlcm5hbWUAcGFzc3dvcmQ=
client -> FAIL 1
c <- no: <nil>
c wait 0