masquerading hostname

[Neelimaix]

Dear all,
we have an application sending email directly from the email server .
the problem is when the customer recieves an email he sees the hostname of the mail server and its not matching with our reverse look up.

is there a way to masqurade the hostname while sending the email. so that the hostname matches the external dns entry.

fox EX:

 

[elgrandeperro]

I think (not absolutely sure) you need to enable MASQUERADE_AS and masquerade_envelope.