Network Tools

Traceroute is one of the most widely used network diagnostic tools — and one of the most misread. When connectivity is degraded or a service is unreachable, traceroute reveals the path packets take from your machine to the destination and shows where the journey breaks down. But the output is dense, and misreading it leads to wrong conclusions: chasing latency spikes that are completely harmless, panicking at asterisks that mean nothing, or missing the one hop that actually indicates a real problem. This guide walks through **how to read traceroute** output correctly, line by line, so you can diagnose network path issues with confidence.

Every IP address you assign, every firewall rule you write, and every cloud VPC you configure rests on the same foundation: an understanding of how IP address space is divided into networks. **Subnetting explained** is the process of splitting a larger block of IP addresses into smaller, logically separated groups — each with its own network address, broadcast address, and range of usable host addresses. CIDR notation is the shorthand that describes those divisions. Once you understand how the two work together, tasks like planning a /24 for a server VLAN, calculating how many hosts fit in a /27, or dividing a /16 into departmental subnets become mechanical rather than guesswork. This guide covers the full picture from IP address structure through practical subnet calculations.

Every packet you send across the internet crosses boundaries between independently operated networks — ISPs, cloud providers, content networks, enterprise networks — each managed by a separate organisation with its own routing policies and business relationships. The protocol that coordinates all of this is BGP (Border Gateway Protocol), and the system it uses to identify each independent network is the Autonomous System Number. **BGP routing explained** is the story of how millions of IP prefixes are announced, filtered, and selected by thousands of networks simultaneously to produce the routing table that determines where every packet goes. This guide covers autonomous systems, how BGP peering and transit relationships work, what the AS path is and why it matters, how route announcements propagate, and what breaks when BGP goes wrong.

Ping is the most widely run network diagnostic command — and the most widely misread. Most people use it to answer a single binary question: is the host reachable? But the numbers in ping output carry significantly more information than a yes/no reachability answer. The **ping test** measures round-trip latency between your machine and a remote host, and the variation and loss patterns in that output reveal the difference between a healthy network path, an overloaded link, a distant route, and a filtering firewall. This guide explains exactly what each field in ping output means, what the TTL value tells you, how to interpret packet loss correctly, what jitter indicates, and when ping is the right tool versus traceroute.