[support] Drupal7 - Hiding Mail server information

Dear All I am trying to send email with attachment in D7/CentOS environment. I faced some difficulties, and implemented on my own to send email with attachment.

If I am sending a plain mail using drupal_mail and hook_mail mechanism, I see in receiving side my mail server details are not shown. If I am sending a plain mail (with or without attachment) using my own implementation I see my server details are there in received mail in Via, Reply-to, and few more headers.

Example: via ip-xxx-xxx-xxx-xx.ip.secureserver.net

How can I suppress http headers carrying my server details like ip-xxx-xxx-xxx-xx.ip.secureserver.net.

Thanks Kamal