My support email is under my main domain as [email protected], but WHMCS is installed under a seperate account secure.mydomain.co.za (with it's own IP), so piping "| php -q /home/username/public_html/whmcs/pipe/pipe.php" from [email protected] won't work. According to http://wiki.whmcs.com/Email_Piping) I'll have to use the CRON Piping method
There is another (better) way
Here is what to do to setup this scenario to work with Email Piping directly into WHMCS:
We're going to use a normal forward from mydomain.co.za to get to secure.mydomain.co.za and then piping from secure.mydomain.co.za into WHMCS using to normal method of "| php -q /home/username/public_html/whmcs/pipe/pipe.php"
1) Login to your WHMCS admin (e.g. at secure.mydomain.co.za/admin) and setup your support department. (Configuration, Support Departments, Add New Dep./Edit existing Dep.)
Make sure that the email address that you specify is the address from your main domain that you want to use, even though it is under a different account/domain. (e.g. [email protected])
2) Then setup a forward for the email address from your main domain that you specified in your Support Department in 1), to an email address on your WHMCS domain. (e.g. Forward [email protected] --> [email protected])
3) Next we will setup the email piping on the mail address on the WHMCS domain using the pipe command supplied by your WHMCS. (e.g. [email protected] --> | php -q /home/secure/public_html/pipe/pipe.php)
All that is left to do is to test your setup. Send a mail to you support department (e.g. [email protected]) from a separate address that is not a admin. When replying as an admin, the response will be sent to the client from the email you specified under you support department.
My example use a sub domain for WHMCS, but you can use a completely separate domain as well, so long as you can send emails as the mail user from your main domain.