Understanding Linux nf_tables: A Plain-English Guide
What Is nf_tables? nf_tables is the modern Linux packet filtering framework. It is the successor to iptables and is built…
Git Fix: fatal: Need to specify how to reconcile divergent branches
What Causes This Error When you run git pull, Git fetches the latest commits from the remote and tries to…
ICMP Type 13 and Type 14 — Timestamp Request / Reply
These are two of the original ICMP message types defined in RFC 792 (1981), alongside echo (ping) and destination-unreachable. They…
Fixing CVE-1999-0524 on Red Hat Enterprise Linux
CVE-1999-0524 is an information-disclosure finding: the host responds to ICMP timestamp requests (type 13) with timestamp replies (type 14), which…
End-to-End Monitoring Checklist for PostgreSQL Logical Replication (Publisher + Subscriber)
Logical replication in PostgreSQL is wonderfully flexible — and wonderfully easy to misdiagnose. When something goes wrong, the symptom is…
How to Split a Large PDF Into Smaller Files
Large PDFs are everywhere — scanned contracts, exported reports, e-books, bank statements — and they’re almost always inconvenient. They’re slow…
Most Linux Engineers Understand SSH -L. Here’s Why SSH -R Is Different
Most Linux engineers learn SSH local port forwarding early in their careers. You have a database running on a remote…
pglogical: The PostgreSQL Logical Replication Power Tool — Complete Guide, Cheat Sheet, and FAQ
Part 1 — Article: Understanding pglogical What is pglogical? pglogical is a PostgreSQL extension developed by 2ndQuadrant (now part of…
pg_top: A Real-Time Monitoring Tool for PostgreSQL
pg_top is a real-time monitoring utility for PostgreSQL, similar to the Linux top command. It allows DBAs and database engineers…
How To Change Hostname in Ubuntu
Setting a unique and descriptive identity for your server is one of the first steps in effective system administration. Without…