Assert SMTP

SMTP is boring, but omnipotent, but it's a the main way to restore passwords.

Check your SMTP relay

For now, there is no dependencies, just a modern python runtime.

The script use ENV variables :

• SMTP_HOST
• SMTP_USER
• SMTP_PASSWORD

Some modern assertions :

• TLS all the time, direct TLS connection or pimp your connection with STARTTLS
• Authentication must be kept simple, juste AUTH PLAIN
• The RFC doesn't specify it, but utf8 is the de facto standard for text encoding

The script tests the 3 SMTP ports :

• 25 should not be used for mail transfer, but for server to server communication
• 465 is no more registered for SMTP at IANA, but it was
• 587 is the current official port for sending mails

The script try to open an smtps connection (no, this protocol name is not yet normalized) and fallback to smtp+starttls.

Authentication with AUTH PLAIN and UTF8 encoding.

No mail is sent.