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How to Set a Hostname and FQDN on RHEL 9 — step-by-step RHEL 9 tutorial on Progressive Robot

How to Set a Hostname and FQDN on RHEL 9

A server’s hostname is its identity on the network. The fully qualified domain name (FQDN) combines the short hostname with the DNS domain, forming an address like web01.example.com. Many services depend on a correctly configured hostname and FQDN to function properly: email servers use the FQDN in SMTP HELO greetings (incorrect values cause delivery rejections), […]

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How to Sync Time with Chrony on RHEL 9 — step-by-step RHEL 9 tutorial on Progressive Robot

How to Sync Time with Chrony on RHEL 9

Accurate time synchronization is not optional on a server — it is a hard requirement. TLS certificate validation fails when the clock is wrong by more than a few minutes. Kerberos authentication rejects tickets with a clock skew over 5 minutes. Cron jobs fire at the wrong time. Log correlation across multiple servers becomes impossible […]

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How to Configure Automatic Security Updates on RHEL 9 — step-by-step RHEL 9 tutorial on Progressive Robot

How to Configure Automatic Security Updates on RHEL 9

Unpatched software is the leading cause of server compromise. The majority of publicly disclosed vulnerabilities already have patches available by the time attackers start actively exploiting them — the window between patch availability and active exploitation has shrunk from months to days. Manually patching servers is error-prone and inconsistent at scale. Automatic security updates ensure […]

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How to Create and Manage Swap Space on RHEL 9 — step-by-step RHEL 9 tutorial on Progressive Robot

How to Create and Manage Swap Space on RHEL 9

Swap space acts as overflow memory. When the physical RAM is full, the Linux kernel moves the least-recently-used memory pages to swap on disk, freeing physical RAM for active processes. Without swap, when RAM is exhausted the Out of Memory (OOM) killer terminates processes — often the largest one, which is frequently your database or […]

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How to Monitor System Resources with htop, top and vmstat on RHEL 9 — step-by-step RHEL 9 tutorial on Progressive Robot

How to Monitor System Resources with htop, top and vmstat on RHEL 9

Every Linux administrator needs a reliable toolkit for answering the question “why is this server slow?” The answer is almost always in one of four resources: CPU, memory, disk I/O, or network. RHEL 9 includes several powerful tools for diagnosing resource contention: top is included in every base installation and provides a real-time process table; […]

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Symfony Messenger and OAuth2

Building Secure Microservices with Symfony Messenger and OAuth2: A Guide to Inter-Service Communication with Confidence

The microservices architecture has revolutionized modern software development, enabling modularity, scalability, and independent deployment of different application functionalities. However, with increased service boundaries comes the critical challenge of secure communication between these services. Symfony Messenger and OAuth2 emerge as powerful tools in this context, offering a robust and elegant solution for building secure microservices in your Symfony applications.

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