SMTP flow----->Postfix:25--------->Product:10025--------->Postfix:10026---->

The basic postfix setting such as domain configuration is ignored.

1. Open the /etc/postfix/main.cf
2. Find key and modify it (if not, add this key)

content_filter = isvw:localhost:10025

3. Open /etc/postfix/master.cf
4. Add the following lines:

      #ISVW add as a smtp client:

isvw      unix  -       -       n       -       70      smtp

           -o   disable_dns_lookup=yes

           -o   smtp_data_done_timeout=1200

           -o   smtp_use_tls=no

           -o   smtp_enforce_tls=no

#ISVW: content filter loop back smtp

localhost:10026  inet   n     -    n    -       70     smtpd

           -o   content_filter=

          -o      local_recipient_maps=

          -o      smtpd_client_restrictions=

          -o      smtpd_use_tls=no

          -o      smtpd_enforce_tls=no

           -o   mynetworks=127.0.0.0/8

          -o      mynetworks_style=host

          -o      smtpd_sender_restrictions=

          -o  smtpd_recipient_restrictions=permit_mynetworks,reject_unauth_destination