Is it possible to have different SMTP banners for different IP addresses on the Plesk server?

Vladimir Levchuk

Updated June 27, 2024 10:50

kb: how-to Plesk for Linux Plesk Obsidian for Linux ABT: Group A

Applicable to:

Each IP address has different PTR records, and they do not match SMTP banners.

There is no such functionality in Plesk yet. Vote for this feature at our User Voice portal.

Perform the following steps as workaround:

Click to expand

To set up SMTP banner for outgoing traffic define smtp_helo_name for specific IP address in /etc/postfix/master.cf configuration file:

CONFIG_TEXT: plesk-203.0.113.2- unix - n n - - smtp -o smtp_helo_name=example2.com -o smtp_bind_address=203.0.113.2 -o smtp_bind_address6= -o smtp_address_preference=ipv4
To set up SMTP banner for incoming traffic do the following in /etc/postfix/master.cf configuration file:

Comment out:

CONFIG_TEXT: smtp inet n - n - - smtpd
Add one entry per address:

CONFIG_TEXT: 127.0.0.1:smtp inet n - n - - smtpd -o smtp_helo_name=localhost -o smtp_bind_address=127.0.0.1 -o myhostname=localhost
x.x.x.x:smtp inet n - n - - smtpd -o smtp_helo_name=mail.domain_x.com -o smtp_bind_address= x.x.x.x -o myhostname= mail.domain_x.com
y.y.y.y:smtp inet n - n - - smtpd -o smtp_helo_name= mail.domain_y.com -o smtp_bind_address=y.y.y.y -o myhostname= mail.domain_y.com

Note: the file may be overwritten during Plesk updates, back it up.