mail() fucntion not sending out any mails

Hello, I have successfully configured PHP4.0.6 on RedHat5.2, all is well but for the mail() which does not send out any mail, it does not return any error either, i tested it with the following code; <?php mail("test@dotcos.com", "Test My Subject", "LiniTeste 1\nLine 2\nLine 3"); ?> This does not return an error but does not send out any mail either, i have also tested this with variety of other parameters/code available at http://www.php.net/manual/en/function.mail.php but still no mail is being send out. I have edited my php.ini file and it looks like this; [mail function] ; For Win32 only. ;SMTP = localhost ; For Win32 only. ;sendmail_from = me@localhost.com ; For Unix only. You may supply arguments as well (default: 'sendmail -t -i'). sendmail_path = sendmail -t -i I have also tried substituting sendmail_path = usr/lib/sendmail , i.e. the path to my sendmail but nothing sems to work here. I am using; PHP4.0.6 sendmail-8.9.3-20.2RS apache-1.3.14-2.2RS Please help me in troubleshooting this. Best Regards, Vivek