[Phphelpdesk-help] mail problem getting mail from another smtp box

[Rolli A. E C. 9. CF/S. <Ada...@ba...>]

I set up the email server in the general.conf.php to my email server
$g_mailservername = "xxx.xxx.xxx.xxx";	//Mail server

but I get emails back from someone elses email server that is on my domain!
I do not have the sendmail daemon running is there another config file? to
stop  this from getting redirected?
thanks
Adam