I have a contant dude connecting to my Postfix, I banned the IP with both smtpd_client_restriction and iptables. I verified it's well setup into iptables, reloaded postfix, but it continues to spill into my logs.
what is this weird thing ?
postfix/smtpd[20244]: connect from unknown[178.215.236.236]
postfix/smtpd[20244]: warning: unknown[178.215.236.236]: SASL LOGIN authentication failed: Invalid authentication mechanism, sasl_username=(unavailable)
postfix/smtpd[20244]: lost connection after AUTH from unknown[178.215.236.236]