Test send email from unix server

$echo "test" | sendmail -v nsanguan@gmail.com


$echo "test" | sendmail -v nsanguan@gmail.com
Warning: .cf file is out of date: sendmail AIX5.3/8.13.4 supports version 10, .cf file is version 9
nsanguan@gmail.com... Connecting to gmail-smtp-in.l.google.com. via esmtp...