I just checked and here's the solution. http://www.linuxquestions.org/questions/linux-networking-3/need-sendmail-guru-149821/#post778024
It was a google's answer. :) good luck. ALFONSO. -----Mensaje original----- De: owner-postfix-us...@postfix.org [mailto:owner-postfix-us...@postfix.org] En nombre de Stefano Villa Enviado el: miƩrcoles, 02 de marzo de 2011 01:42 p.m. Para: postfix users Asunto: info about a Sendmail configuration Hi to all! Sorry for my question about Sendmail and not Postfix.. but I'm in trouble! Here the question. I've a Red Hat server (hostA.domain1.dom) that should send mail trough an Exchange server (hostB.domain2.dom) to a destination address. The Exchange rejects the message because it does not recognize my domain (*.domain1.dom) What should I do in the sendmail.cf to permit the change of "from" field from *.domain1.dom to *.domain2.dom? p.s.: I cannot modify the Exchange configuration to add domain1.dom to known domains.. Thanks in advance! -- Stefano Villa