There are at least two basic authentication methods: AUTH PLAIN and AUTH LOGIN. libcurl 7.35 supports both of them. When CURLOPT_LOGIN_OPTIONS is set to “AUTH=PLAIN” then AUTH PLAIN method is used. When CURLOPT_LOGIN_OPTIONS is set to “AUTH=LOGIN” then AUTH LOGIN method is used. Zabbix 3.0 media types configuration allows to choose only AUTH PLAIN method. An AUTH LOGIN option in the media types configuration would be very helpful to connect some SMTP servers. Also an automatic detection of basic authentication method will be considered as more friendly.

AUTH LOGIN session example:
S: 220 smtp.server.com ESMTP
C: EHLO client.example.com
S: 250-smtp.server.com Hello client.example.com
250-SIZE 1000000
250-PIPELINING
250-DSN
250-ENHANCEDSTATUSCODES
250-STARTTLS
250-AUTH LOGIN
250-8BITMIME
250-BINARYMIME
250 CHUNKING
C: AUTH LOGIN
S: 334 VXNlcm5hbWU6
C: adlxdkej
S: 334 UGFzc3dvcmQ6
C: lkujsefxlj
S: 235 2.0.0 OK