Add a Spam Filter to a Plesk Server

Learn how to install the SpamAssassin spam filter on a 1&1 Cloud Server with Plesk. A spam filter is a necessary tool for any mail server. SpamAssassin is easy to install and manage with Plesk, and will filter out spam which is sent to email mailboxes hosted by your 1&1 Cloud Server. [...]  

Troubleshoot SMTP Error 550 "Relay Denied"

Learn how to resolve the common e-mail error SMTP 550 "Relay Denied." This error most often happens because of a failure to correctly authenticate with the SMTP server. Learn more about SMTP authentication methods, and how to resolve this error. [...]  

Email Protocols: POP3 vs IMAP

Learn about the difference between POP3 and IMAP e-mail protocols, find out which one will serve your needs best, and learn about the potential consequences of your users choosing one over the other. [...]  

Managing Email on 1&1 Cloud Servers

Learn more about using email with a 1&1 Cloud Server account, including how to set up and use the 1&1 Webmail included with each account, how to configure the DNS and firewall if you prefer to host your own email server, and more. [...]  

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