How to Limit the Number of Outgoing Messages in Plesk

How to Limit the Number of Outgoing Messages in Plesk
If you are managing your own server, it is important to know that we should set a limit to the number of outgoing messages for each of the email accounts. Spam is a huge issue on the internet and we should take some measurements to protect our servers from being used by the spammers to send out bulk unsolicited e-mail. By limiting the number of emails that each email account can send out per hour, it would minimize the impact when hijackers succeed in hijacking your users' accounts to send out spam emails. It would give you some time to deal the compromised email account before your server IP address is blacklisted on the DNS based blacklists like DNSBL (A Domain Name System-based Blackhole List) or RBL (Real-time Blackhole List). If your server IP address is listed on the blacklists, it will impact your mail server reputation and other mail servers may reject the emails that delivered from your server.

In general, most server control panels provide functionality to limit the number of outgoing messages. In this post, I’ll show you the ways to limit outgoing messages in the Plesk control panel. Please take note that this functionality is only supported on the Plesk version 12.0 and above.

Launch your web browser and sign in to your Plesk account as you normally would. Click on Tools & Settings link under the Server Management on the left.
Tools and Settings Plesk

Then click on the Mail Server Settings under Mail. Scroll down and check the option Switch on Limitations on outgoing email messages. Uncheck the unlimited check boxes for Default Limit on outgoing messages from a domain (per hour) / subscription (per hour) and enter the limit for the number of messages can send per hour. Click on OK button at the bottom to apply the changes.
Limit the Number of Outgoing Messages in Plesk

If you would like to set up limits for an individual email account, go to Domains,, Email Addresses, select the email address for which you want to change the limit and click on Limit Outgoing Message. Enter the desired value to limit the outgoing messages (per hour) for this email account. Click on OK button to apply the changes.