nano /etc/mail/mailertable
and add a line for each domain you want to handle in the form:
yourdomain.com smtp:[your.target.ip]
Next, add the domains you want to wash for in the gui, under
EMAIL, Advanced, 'Relay email from domains'
run
newaliasesrun
/etc/init.d/sendmail restartFinaly, point the MX records for the domain to the cobaltclone box. The machine will now accept mail for the domain, run it though any optional scans you install (such as clamav, mailscanner, spamassassin) and then offload the mail to the ip address you specified.