Subnetting and CIDR Explained with Simple Examples
Learn subnetting fast: CIDR prefixes, masks, block-size trick, splitting networks, private ranges and tools to check your math.
yuri@itblogs: ~
$ cat README.md # Personal IT knowledge base Fixes, snippets and notes from real-world work: Linux, networking, servers, DevOps. $ ls posts/ | wc -l 24$
DNS Troubleshooting Guide: dig, nslookup and Common Problems
Diagnose DNS issues with dig, nslookup and Resolve-DnsName: record types, status codes, TTL, flushing caches and the usual causes.
Diagnose Network Connectivity Step by Step: ping, mtr, nc, tcpdump
A layered method to find network problems: what refused and timed out really mean, mtr and traceroute, MTU tests and packet capture.
Set Up a WireGuard VPN Server on Ubuntu 24.04
Build a WireGuard VPN on Ubuntu 24.04: keys, server and client configs, NAT and firewall rules, full or split tunnel, and troubleshooting.