Limiting Outgoing Mail

Your hosting provider can impose limitations on the number of outgoing email messages per hour, usually in order to restrict possible spam. A subscription, domain, and mailbox have their own limits. By default, values for the limits are defined by the hosting provider.

You might want to increase the limits to send more email messages, or decrease the limits to prevent excessive outgoing mail.

The number of outgoing email messages sent from a parent object (such as a subscription) is counted as the sum of email messages from its child objects (such as domains). And limits work accordingly:

  • The sum of messages from all domains of a subscription cannot be greater than the subscription’s limit.
  • The sum of messages from all mailboxes of a domain cannot be greater than the domain’s limit.

Note

The limit of a parent object is more important than individual limits of child objects. For example, if the limit for a subscription is reached, no domains of this subscription can send mail, even when some of the domains have not yet reached their individual limit. Similarly, if the limit for a domain is reached, no mailboxes of this domain can send mail, regardless of the fact that some of the mailboxes have not reached their individual limit.

Note

The options described below are displayed only if the limitations on outgoing mail are switched on by your hosting provider. Also, some limits might be unavailable (for example, the limit on the number of outgoing email messages from a mailbox), depending on the mail server used in Plesk.

To set up limits on the number of outgoing email messages for a domain:

  1. Go to Mail > the Mail Settings tab and select one or more domains for which you want to change the limit, by using checkboxes.
  2. Click Limit Outgoing Messages on the toolbar.
  3. Edit the Limit on outgoing messages field.

To set up limits on the number of outgoing email messages for a mailbox:

  1. Go to Websites & Domains > Mail Settings of the domain where the mailbox belongs > the Email Addresses tab and select one or more email addresses for which you want to change the limit, by using checkboxes.

  2. Click Limit Outgoing Messages on the toolbar.

  3. Edit the Limit on outgoing messages field.

    Alternatively, you can click the email address and edit The maximum number of outgoing email messages.

To see detailed statistics and edit limits on outgoing messages (for a subscription):

  1. Go to Websites & Domains > Outgoing Mail Control.

    Alternatively, you can go to Websites & Domains > Mail Settings of the main domain > the Outgoing Mail Control tab, and click the Outgoing Mail Control link there.

  2. The General tab shows the number of Plesk objects that have attempted to exceed limits, and the list of such objects.

  3. To see details about a certain Plesk object, go to the corresponding tab (Email Addresses, Domains, or Subscriptions), click the required object and view the report Attempts to send mail after reaching the limit.

    Also, in the Sent messages section, daily per-hour statistics are available for a certain Plesk object: You can see the number of attempts to send excessive mail by each hour of a certain day.

Note

Messages sent to mailing list subscribers are not counted in Outgoing Mail Control.

Outgoing Mail Limit Calculation

The outgoing mail limit is calculated over a rolling window of one hour. It means that each attempt to send an email triggers calculation of all emails sent within the last hour. For example, you try sending an email at 9:15. To determine the limit, Plesk calculates all emails sent from 8:15 to 9:15. If the limit is not exceeded, the email is sent. Otherwise, the email is not sent, and you can see an error of the following pattern in /var/log/maillog:

Your message could not be sent.
The limit on the number of allowed outgoing messages was exceeded. Try again later.

You can also see that the limit was exceeded in Tools & Settings > Outgoing Mail Control (under “Mail”).

image-outgoing-mail-limit

Note

Outgoing Mail Control appears in the Plesk interface if the “Turn on limitations on outgoing email messages” checkbox is selected (Tools & Settings > Mail Server Settings (under “Mail”) > the “Limitations on outgoing email messages” section).

Note

Unlike /var/log/maillog, the Plesk interface shows only the approximate time when the limit was exceeded.

Outgoing Mail Limit Calculation and Mail Forwarding

Mailboxes that have mail forwarding to other mailboxes configured via Plesk receive one or more outgoing emails per a received one. These forwarded emails are counted against the outgoing mail limit. It is true even if mailboxes where emails are being forwarded to are hosted on the same Plesk server.