Outgoing Mail from Exclusive IP Addresses

In Plesk versions earlier than 11.5, the outgoing mail of all customers
was sent from a single IP address (defined by the mail server
configuration). Thus, if one of the customers became blacklisted for
sending spam, other customers were automatically blacklisted too since
they used the same IP address. Also, if a customer had several IP
addresses, and the address for outgoing mail did not match the address
of the domain, the customer run a risk to be blacklisted as well.

In Plesk 11.5, the problem of domain and mail addresses is resolved, and
Postfix mail server uses customers’ IP addresses for sending mail if
possible. This targets all outgoing mail of the Plesk mail server sent
by PHP mail(), sendmail, an SMTP script or client. However, if the
following conditions are true, your system can send mail from different
IP addresses:

• You have Postfix 2.7
• Plesk is configured to support IPv6
• A subscription has only a single IPv4 or IPv6

The outgoing mail for such subscriptions can be sent from either the
customer’s IP address or an IP address of one type (IPv6 for IPv4 and
vice versa) specified in the mail server configuration.

Another part of this feature is the sender’s address validation: The
system validates the MAIL FROM header for authenticated users and
corrects the header if needed. However, if the mail is sent without
authentication, for example, from 127.0.0.1, through the local sendmail,
or a sender is in the white list, the system trusts the MAIL FROM
header.

And in case you need to send all mail from one specific IP address, you
can specify one IPv4 or one IPv6 address from which all mail will be
sent. All corresponding settings are available in the Plesk GUI in Plesk
for Linux with Postfix as a mail server. For details, see the Plesk
Administrator’s Guide, Configuring Server-Wide Mail
Settings.

Requirements

This feature is supported on all operating systems that have Postfix 2.7
or later. They are as follows: