Spam mails are a nuisance! They are often silly and non-threatening mails coming to users’ inbox, and all the users may have to do is to delete it or mark it as spam.
But spam mails can quickly turn into terror when attackers spam server. Too much inbound spamming to your mail server can cause the mail queue to fill up and delay email delivery or even crash it.
Amazon claims to have a system to white-list all their IP addresses at Spamhaus regularly. But we still see Amazon EC2 users reporting mail issues due to IP blacklists by Spamhaus.
IP blacklisting occur when your mail server gets compromised due to any malware or open vulnerabilities. Attackers can hijack your mail server and send spam mails from it. (more…)