So, the commands by order:
- gnetinfo http://www.senderbase.org/senderbase_queries/detaildomain?search_string=mail.sic.pt
- dig mx sic.pt (resulted in mail.sic.pt)
- gmailkind exercise -v -v --test-from legitimate_sender@known_domain --test-rcpt abuse@sic.pt -v mail.sic.pt (resulted in SMTP 550 response, which violates SMTP RFC)
The story for this: rfc-ignorant.org
You can use the "Ignorant" lists as you like, as a postmaster / mail administrator.
Currently I do not know what being listed at the RFC ignorant might mean, but I can learn.
Hint: DNSing example.tld.dsn.rfc-ignorant.org will provide you the status of the domain.
