Im adding a second email server in the same company.com domain , one its postfix , and the new one its exchange 2007 , I need your help in order to be available to send email from users in exchange server to users in postfix.Im know how to do it in the opposite way , means users from postfix to user in exchange.Please advice.Thanks

If you use the same SMTP domain, you need to provision Exchange with contacts referring to the Postfix installation and use a internal routing domain to route to Postfix. This is because Exchange will only accept mail for local delivery if it is authoritive for the domain. If exchange is authoritive for a domain and it does not find a recipient in AD it will drop the email. There for mail contacts with a External Mailaddress will be used to route the email to another environment. So what to do.... (I will post some CMDLET examples, but all of the Exchange stuff can be done via the GUI. Just check the Exchange documentation) 1. Create a new emaildomain (non-routable on the internet, for example domain.local) for which postfix will be authoritive 2. Add an secondary email address to the postfix users for the new emaildomain. 3. Create Mail contacts in Exchange 2007with the domain.local address as external address: New-MailContact -ExternalEmailAddress 'SMTP:test@domain.local' -Name 'test' -Alias 'test' -OrganizationalUnit 'domain.com/OU' -FirstName 'test' -Initials '' -LastName '' 4. You need to add the domain.com emailaddress of the postfix accounts to the mail contact if the recipient policy did not already do that. 5. Create a send connector in Exchange to route this new domain to postfix: new-SendConnector -Name 'TEST' -Usage 'Internal' -AddressSpaces 'smtpomain.local;1' -DNSRoutingEnabled $false -SmartHosts 'yourpostfixserver.domain.com' -SmartHostAuthMechanism 'None' -UseExternalDNSServersEnabled $false -SourceTransportServers 'yourexchange2007server.domain.com' Now send some test mails. You should be up and running now. Cheers, Mark