<p>We currently have VM environment setup with an internal network and a DMZ network. Historically we had no open ports between these environments, but needs arose for communication between the internet and services/APIs running on our internal servers.</p>
<p>We decided to use our DMZ network as a proxy/gateway, where we specifically use Kong Gateway, exposing ports 80/443 to the internet, and then proxying/forwarding requests through a different port opened up between the DMZ server and the specific internal server that needs to handle this communication. A random, non-standard, high port is being used for <em>all</em> requests between the DMZ server and our internal network, and we then use a reverse proxy on our internal server to route specific request via hostnames to specific APIs/services on the internal server.</p>
<p>Now, we're in the process of converting our internal environment to a k8s cluster, and I'm interested in knowing if there'd be any &quot;real&quot; difference to security, if we were to forego the DMZ proxy, and exposing ports 80/443 directly from the internet to our internal k8s cluster, and handle all the security/authentication/authorization through the ingress controller on our cluster.</p>
<p>It would simplify our infrastructure a decent bit, to not have this DMZ proxy running.</p>
<p>From my understanding the purpose of the DMZ proxy was that if a breach were to happen in the chain, it would be much harder to further penetrate our internal network, if the breach was only on the DMZ server. But my networking and security knowledge is not good enough to say if this is actually true, and it just provides a false sense of extra security, in which case, we'd have the exact same level of security with exposing those same ports directly on our internal k8s cluster, while simplifying the overall infrastructure.</p>

Dynde
<blockquote>
<p>if there'd be any &quot;real&quot; difference to security, if we were to forego the DMZ proxy, and exposing ports 80/443 directly from the internet to our internal k8s cluster, and handle all the security/authentication/authorization through the ingress controller on our cluster.</p>
</blockquote>
<blockquote>
<p>It would simplify our infrastructure a decent bit, to not have this DMZ proxy running.</p>
</blockquote>
<p>You probably want a &quot;Gateway&quot; outside the cluster, with a <strong>static</strong> IP-address. The nodes in the cluster are more <em>dynamic</em>, you want to throw away the old and create new when upgrading e.g. the linux kernel.</p>
<blockquote>
<p>From my understanding the purpose of the DMZ proxy was that if a breach were to happen in the chain, it would be much harder to further penetrate our internal network, if the breach was only on the DMZ server.</p>
</blockquote>
<p>The book <a href="https://rads.stackoverflow.com/amzn/click/com/1491962194" rel="nofollow noreferrer" rel="nofollow noreferrer">Zero Trust Networks</a> is good about this. Things has changed, the older way of using &quot;DMZ&quot; to protect internal networks, called &quot;perimeter security&quot; is now replaced with a &quot;Zero Trust Networking&quot; model. Now every host (or Pod) should be responsible for its security, on Kubernetes, to get this hardened, you can use a &quot;Service Mesh&quot; to implement mutual TLS between all services, see e.g. <a href="https://istio.io/" rel="nofollow noreferrer">istio</a>.</p>
