DMZ, help needed for UTM 9.4 (software) configuration.

Question

Hi,
Need help with setting up a DMZ network on my UTM 9.4 firewall computer.
I have tried to set this up for a long time but with no luck.
And I have also tried a lot of different settings (from forum and Internet) for my DMZ but it never works.

I have 3 NIC:s with following configuration:
eth0 = Internal with 172.21.21.10/16
eth1 = External with a static IP address xxx.xxx.xxx.xxx/27
eth2 = DMZ with 10.0.0.1/28

DNS Allowed network =
Internal (Network)
DMZ (network)

NAT Masquerading rule =
Internal (Network) - External (WAN)
DMZ (Network) - External (WAN)

Firewall rules =
DMZ (Network) - reject - Internal (Network)
DMZ (Network) - allow - External (WAN) (Network)
DMZ (Network) - allow - DMZ (Network)

What's wrong? More NAT rules? More Firewall rules? More what???

Please give me some hints how to config my UTM.

rgds Roland

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BAlfson · Answer

Hi, Roland, and welcome to the UTM Community! 
 It's your firewall rules. First, everything that isn't explicitly allowed is blocked. Things like VPNs and Proxies create hidden firewall Allow rules. It appears that you already have understood that the UTM is a stateful firewall, so it automatically allows inbound responses to requests that were allowed out. 
 Instead of rejecting traffic DMZ -> Internal: 
 
 Internal (Network) -> {services} -> Any : Allow 
 DMZ (Network) -> (Services} -> Internet : Allow 
 
 You don't need to allow traffic between devices in the DMZ as all traffic between devices with the same subnet on the same Ethernet segment goes directly between the devices and does not transit the UTM. 
 All good now? 
 Cheers - Bob

DMZ, help needed for UTM 9.4 (software) configuration.

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