Hi,
Can i put my Exchange Server, Domain Controller and Oracle all together in the DMZ Zone.
One of my friend suggest that leave Domain outside the DMZ zone my issue is that all my servers under 1 subnet only.
Thanks,
nidz
Hi nidz,
your idea does not make any sense from a security perspective. The domain controller contains sensitive information like user data, passwords and other. A domain controller manages your internal network and simply has no business in the DMZ. Don't do this. Interesting blog article: https://www.linkedin.com/pulse/active-directory-dmz-nuts-marcus-rivera/
Database servers is something else, depends on the database. In general, databases should be secured and placed also internally. But sometimes you install databases together with a webserver on the same host. If you need people to connect without VPN to a dedicated database, of course you can put in the DMZ. But secure it as much as you can through firewall policies and host-specific settings. Search for some best practises how to secure the database server and what specific WAF settings you should apply to secure the DB server. Maybe also some DB engineers are present here in the forums and may help you out 
Exchange Server is okay to put in the DMZ as your users may use Exchange OWA to access their emails. When installing Exchange Server, you can install one of the two roles:
Every Exchange role functions for a different purpose, if it’s a Mailbox role or Edge Transport role. That’s why the best practice is to place the Exchange Mailbox server in the LAN network. The best practice to place the Exchange Edge Transport server is in DMZ network. Both of the Exchange server roles need different network ports to get the mail flow working.
More Info about Exchange and the DMZ (also the source for the above image): https://www.alitajran.com/exchange-server-in-dmz-or-lan-network/#:~:text=The%20best%20practice%20to%20place,traffic%20between%20internal%20Exchange%20servers.
Regards
