Hi, I have a customer with a sun cobalt running Sendmail 8.10.2/8.10.2 and we are phasing out the sun cube due to some limitations. So we have installed a new centos 5.x server. the format of our current emails are username at domain.com and the new format will be name.lastname at domain.com. We have 1600 accounts. Both server are in the LAN. The MX record that the world sees, point to our current AV/AntiSpam appliance, then our AV appliance forwards to the mail server (its a trendmicro IMSS) The AV appliance lets me define rules that emails for username at domain.com should be sent to the mailserver with the cube, and it also let me define a rule for name.lastname at domain.com to be sent to the centos machine, so I have covered the "from internet" inbound email issue. going out to the internet, both servers can send emails perfectly. However, Since both servers will "answer" to the same domain, i need some guidance as to how to 1- If user hosted on the Sun sendmail Cube sends emails to name.lastname at domain.com, make the Cube forward/send the email to the Centos machine. 2- If user hosted in centos, sends email to username at domain.com, make the POSTFIX forward/send the email to the Cube machine. Due to internal regulations i must say that: 1- users cannot be moved all at once. 2- centos machine must use postfix - not sendmail. I can however, install sendmail on centos and make it listen in another port other than 25 if some solution arises that needs sendmail in both sides. Anyways, any guidance as to how to solve this mess is welcomed!!!! Thanks, -- ------------------------------------------------------------ Erick Perez Panama Sistemas Integradores de Telefonia IP y Soluciones Para Centros de Datos Panama, Republica de Panama Cel Panama. +(507) 6694-4780 ------------------------------------------------------------