- Plesk for Linux
How to disable mail() function for a spamming domain on Plesk server?
How to prevent e-mails from being sent via scripts through Sendmail?
Click on a section to expand
To disable PHP mail() function for a domain, follow the steps below:
Go to Subscriptions > example.com > Customize > PHP settings
disable_functions = mailstring to the Additional configuration directives field:
- Click OK button to apply changes
Note: Make sure that the corresponding subscription is locked, otherwise the global definitions of that subscription plan will be synced and the domain's specific configuration will be lost.
disable_functions = mail is set, but 'mail' is not listed as disabled in Domains > example.com > PHP Settings > phpinfo (), check if some additional PHP modules are installed on the server. Additional PHP modules can overwrite
settings for the domain.
In case Suhosin PHP module is installed, follow these steps:
Connect to the server via SSH and comment out
disable_functionsdirective in Suhosin config in order not to override the same directives in domains
# grep disable_function /etc/php.d/suhosin.ini
Add additional PHP directive for domain:
CONFIG_TEXT: disable_functions = exec, system, mail
Note: If mail() function is disabled for PHP, but emails are still being sent by unidentified script, Sendmail can be disabled completely.
Usage of Sendmail utility can be disabled server-wide with the settings at:
- Log in to Plesk GUI > Tools & Settings > Mail Server Settings > Disable the option Allow scripts and users to use Sendmail
Or at Service Plan level:
- Log in to Plesk GUI > Service Plans > <service_plan_name> > Mail > Disable the option Allow scripts and users to use Sendmail
Or at Subscription level:
- Log in to Plesk GUI > Subscriptions > example.com > Outgoing mail control > Subscription > Change limits > Disable the option Allow scripts and users to use Sendmail
Also, it is possible to block all outgoing mail that is being sent by PHP scripts like PHPMailer by adding the following iptables rule (on RHEL/CentOS):
- Connect to the server via SSH
- Save the current iptables rules to the file:
# iptables-save > /root/pre_iptables_rules
- Add the rule that blocks all outgoing packets send by processes where the owner is not postfix excluding local connections from Webmail:
# iptables -I OUTPUT -m owner ! --uid-owner postfix -m tcp -p tcp --dport 25 ! -d 127.0.0.1 -j REJECT
- Install and enable necessary package:
# yum install iptables-services && systemctl enable iptables-services
- Save iptables rules to make the changes permanent:
# /sbin/service iptables save