A method of establishing a connection to a securednetwork or computer within a network that does not have an open port. Aremote device sends a series of series of connection attempts, in the form ofpackets, to the computer??s closed ports, and the attempts are silently ignored but logged by the firewall. When the remote device has established the predetermined sequence of port connection attempts, a daemon triggersa port to open, and the network connection is established. This security method is analogous to knowing a "secret knock," and only people who know the proper knock sequence will be allowed access. An advantage of using a port knocking technique is that a malicious hacker cannot detect if a device is listening for port knocks.
Fixing Tanzu Kubernetes Pod to External Services Connectivity Issues with NSX-T Last month I got a call from a customer who was pulling their hair out over a networking issue. They had just deployed VMware Tanzu Kubernetes Grid on their vSphere with Tanzu environment, everything looked good in the dashboards, all pods were running, but their applications inside the pods could not reach external databases running on traditional VMs in the same datacenter. The frustrating part was that some pods could reach external services perfectly fine, while others would just timeout. There was no clear pattern. Let me tell you how we figured this out and fixed it. The Initial Problem Here is what the customer setup looked like: vSphere 8.0 with Tanzu enabled NSX-T 4.1.2 for networking Three Tanzu Kubernetes clusters running different microservices applications External PostgreSQL database running on traditional VMs (non-Kubernetes) External API services running on another se...