Symptoms1. Install Plesk 11 server
2. Create domain with PHP "on"
3. Create mail name on this domain with enabled Webmail
3. Modify /etc/php5/apache2/php.ini
; This directive allows you to disable certain functions for security reasons.
; It receives a comma-delimited list of function names. This directive is
; *NOT* affected by whether Safe Mode is turned On or Off.
disable_functions = "popen,exec,system,passthru,proc_open,shell_exec"
4. Try to send mail via Webmail
Actual result: Mail is not sent.
ResolutionRevert changes in server wide php.ini.
Plesk has own management for php.ini per service plan, per subsription and per website.