https://cyclechain.io/blog/en/tags/network-diagnostics/Recent content in Network-Diagnostics on Cyclechain BlogHugoenWed, 26 Nov 2025 15:57:21 +0000https://cyclechain.io/blog/en/p/anatomy-of-network-diagnostics-icmp-ping-mtr/Wed, 26 Nov 2025 15:57:21 +0000https://cyclechain.io/blog/en/p/anatomy-of-network-diagnostics-icmp-ping-mtr/<details class="toc-accordion"> <summary class="toc-accordion-title">Table of Contents</summary> <nav class="toc-accordion-content"> <nav id="TableOfContents"> <ul> <li><a href="#introduction">Introduction</a></li> <li><a href="#history-and-evolution-of-the-internet">History and Evolution of the Internet</a> <ul> <li><a href="#arpanet-where-it-all-started-1969">ARPANET: Where It All Started (1969)</a></li> <li><a href="#birth-of-tcpip-1970s">Birth of TCP/IP (1970s)</a></li> <li><a href="#expansion-of-the-internet-1980-1990s">Expansion of the Internet (1980-1990s)</a></li> </ul> </li> <li><a href="#how-does-the-internet-work-down-the-rabbit-hole">How Does the Internet Work? Down the Rabbit Hole</a> <ul> <li><a href="#packet-switching-the-foundation-of-internet">Packet Switching: The Foundation of Internet</a></li> <li><a href="#tcpip-model-4-layer-architecture">TCP/IP Model: 4-Layer Architecture</a> <ul> <li><a href="#1-network-interface-layer-link-layer">1. Network Interface Layer (Link Layer)</a></li> <li><a href="#2-internet-layer">2. Internet Layer</a></li> <li><a href="#3-transport-layer">3. Transport Layer</a></li> <li><a href="#4-application-layer">4. Application Layer</a></li> </ul> </li> <li><a href="#routing-how-do-packets-find-their-way">Routing: How Do Packets Find Their Way?</a></li> </ul> </li> <li><a href="#icmp-protocol-the-nervous-system-of-the-internet">ICMP Protocol: The Nervous System of the Internet</a> <ul> <li><a href="#what-is-icmp">What is ICMP?</a></li> <li><a href="#why-is-icmp-needed">Why is ICMP Needed?</a></li> <li><a href="#icmp-message-structure">ICMP Message Structure</a></li> <li><a href="#important-icmp-message-types">Important ICMP Message Types</a> <ul> <li><a href="#type-08-echo-reply--echo-request-ping">Type 0/8: Echo Reply / Echo Request (PING)</a></li> <li><a href="#type-3-destination-unreachable">Type 3: Destination Unreachable</a></li> <li><a href="#type-11-time-exceeded">Type 11: Time Exceeded</a></li> <li><a href="#type-5-redirect">Type 5: Redirect</a></li> <li><a href="#type-30-traceroute">Type 30: Traceroute</a></li> </ul> </li> <li><a href="#security-aspect-of-icmp">Security Aspect of ICMP</a></li> </ul> </li> <li><a href="#ping-command-the-heart-of-network-diagnostics">Ping Command: The Heart of Network Diagnostics</a> <ul> <li><a href="#what-is-ping">What is Ping?</a></li> <li><a href="#how-does-ping-work">How Does Ping Work?</a></li> <li><a href="#basic-ping-usage">Basic Ping Usage</a> <ul> <li><a href="#simplest-usage">Simplest Usage</a></li> </ul> </li> <li><a href="#ping-parameters-and-usage-examples">Ping Parameters and Usage Examples</a> <ul> <li><a href="#1-limiting-packet-count--c--count">1. Limiting Packet Count (-c / &ndash;count)</a></li> <li><a href="#2-changing-packet-interval--i--interval">2. Changing Packet Interval (-i / &ndash;interval)</a></li> <li><a href="#3-changing-packet-size--s--size">3. Changing Packet Size (-s / &ndash;size)</a></li> <li><a href="#4-setting-ttl-value--t---ttl">4. Setting TTL Value (-t / -ttl)</a></li> <li><a href="#5-flood-ping--f---use-carefully">5. Flood Ping (-f) - Use Carefully!</a></li> <li><a href="#6-timestamp--d--timestamp">6. Timestamp (-D / &ndash;timestamp)</a></li> <li><a href="#7-specifying-source-address--i--interface">7. Specifying Source Address (-I / &ndash;interface)</a></li> <li><a href="#8-ipv6-ping">8. IPv6 Ping</a></li> <li><a href="#9-quiet-mode-and-verbose--q---v">9. Quiet Mode and Verbose (-q / -v)</a></li> <li><a href="#10-timeout-setting--w--timeout">10. Timeout Setting (-W / &ndash;timeout)</a></li> </ul> </li> <li><a href="#real-world-ping-examples-and-analysis">Real World Ping Examples and Analysis</a> <ul> <li><a href="#example-1-healthy-connection">Example 1: Healthy Connection</a></li> <li><a href="#example-2-packet-loss-present">Example 2: Packet Loss Present</a></li> <li><a href="#example-3-high-latency">Example 3: High Latency</a></li> <li><a href="#example-4-host-unreachable">Example 4: Host Unreachable</a></li> <li><a href="#example-5-request-timeout-firewall">Example 5: Request Timeout (Firewall)</a></li> <li><a href="#example-6-fragmentation-problem">Example 6: Fragmentation Problem</a></li> </ul> </li> <li><a href="#troubleshooting-strategy-with-ping">Troubleshooting Strategy with Ping</a></li> </ul> </li> <li><a href="#mtr-my-traceroute---advanced-network-diagnostics-tool">MTR: My Traceroute - Advanced Network Diagnostics Tool</a> <ul> <li><a href="#what-is-mtr">What is MTR?</a></li> <li><a href="#mtr-vs-ping-vs-traceroute">MTR vs Ping vs Traceroute</a></li> <li><a href="#how-does-mtr-work">How Does MTR Work?</a></li> <li><a href="#mtr-installation">MTR Installation</a></li> <li><a href="#basic-mtr-usage">Basic MTR Usage</a> <ul> <li><a href="#simple-usage">Simple Usage</a></li> </ul> </li> <li><a href="#mtr-parameters">MTR Parameters</a> <ul> <li><a href="#1-report-mode--r--report">1. Report Mode (-r / &ndash;report)</a></li> <li><a href="#2-interval-setting--i--interval">2. Interval Setting (-i / &ndash;interval)</a></li> <li><a href="#3-packet-size--s--psize">3. Packet Size (-s / &ndash;psize)</a></li> <li><a href="#4-ip-version-selection--4---6">4. IP Version Selection (-4 / -6)</a></li> <li><a href="#5-using-tcp-or-udp--t---u">5. Using TCP or UDP (-T / -u)</a></li> <li><a href="#6-maximum-hop-count--m--max-ttl">6. Maximum Hop Count (-m / &ndash;max-ttl)</a></li> <li><a href="#7-disable-hostname-resolution--n--no-dns">7. Disable Hostname Resolution (-n / &ndash;no-dns)</a></li> <li><a href="#8-show-as-number--z--aslookup">8. Show AS Number (-z / &ndash;aslookup)</a></li> <li><a href="#9-csvjsonxml-output">9. CSV/JSON/XML Output</a></li> <li><a href="#10-interactive-mode-shortcuts">10. Interactive Mode Shortcuts</a></li> </ul> </li> <li><a href="#real-world-mtr-examples-and-analysis">Real World MTR Examples and Analysis</a> <ul> <li><a href="#example-1-healthy-connection-1">Example 1: Healthy Connection</a></li> <li><a href="#example-2-problem-at-specific-hop">Example 2: Problem at Specific Hop</a></li> <li><a href="#example-3-asymmetric-routing">Example 3: Asymmetric Routing</a></li> <li><a href="#example-4-icmp-rate-limiting">Example 4: ICMP Rate Limiting</a></li> <li><a href="#example-5-geographic-latency-pattern">Example 5: Geographic Latency Pattern</a></li> <li><a href="#example-6-packet-loss-pattern-analysis">Example 6: Packet Loss Pattern Analysis</a></li> </ul> </li> <li><a href="#advanced-mtr-usage">Advanced MTR Usage</a> <ul> <li><a href="#1-continuous-monitoring-script">1. Continuous Monitoring Script</a></li> <li><a href="#2-multiple-target-comparison">2. Multiple Target Comparison</a></li> <li><a href="#3-parsing-json-output">3. Parsing JSON Output</a></li> <li><a href="#4-creating-graphics-mtr--gnuplot">4. Creating Graphics (mtr + gnuplot)</a></li> </ul> </li> <li><a href="#interpreting-mtr-output-best-practices">Interpreting MTR Output: Best Practices</a> <ul> <li><a href="#1-interpreting-packet-loss">1. Interpreting Packet Loss</a></li> <li><a href="#2-latency-pattern-analysis">2. Latency Pattern Analysis</a></li> <li><a href="#3-jitter-stdev-evaluation">3. Jitter (StDev) Evaluation</a></li> </ul> </li> </ul> </li> <li><a href="#real-world-scenarios-and-problem-solving">Real World Scenarios and Problem Solving</a> <ul> <li><a href="#scenario-1-internet-is-slow-complaint">Scenario 1: &ldquo;Internet is Slow&rdquo; Complaint</a></li> <li><a href="#scenario-2-website-sometimes-opens-sometimes-doesnt">Scenario 2: Website Sometimes Opens, Sometimes Doesn&rsquo;t</a></li> <li><a href="#scenario-3-poor-voip-call-quality">Scenario 3: Poor VoIP Call Quality</a></li> <li><a href="#scenario-4-slowdown-at-specific-times">Scenario 4: Slowdown at Specific Times</a></li> <li><a href="#scenario-5-multi-path-routing-detection">Scenario 5: Multi-Path Routing Detection</a></li> </ul> </li> <li><a href="#advanced-tips-and-best-practices">Advanced Tips and Best Practices</a> <ul> <li><a href="#1-optimizing-icmp">1. Optimizing ICMP</a></li> <li><a href="#2-firewall-and-icmp">2. Firewall and ICMP</a></li> <li><a href="#3-mtr-vs-traceroute">3. MTR vs Traceroute</a></li> <li><a href="#4-performance-monitoring-dashboard">4. Performance Monitoring Dashboard</a></li> <li><a href="#5-mtr-for-mobileremote-work">5. MTR for Mobile/Remote Work</a></li> </ul> </li> <li><a href="#conclusion">Conclusion</a> <ul> <li><a href="#summary-of-what-weve-learned">Summary of What We&rsquo;ve Learned:</a></li> <li><a href="#mastering-yoda--resources">Mastering Yoda &amp; Resources:</a></li> <li><a href="#final-word">Final Word</a></li> </ul> </li> </ul> </nav> </nav> </details> <style> .toc-accordion { margin: 2em 0; border: 1px solid var(--code-border, rgb(50, 50, 50)); border-radius: 8px; overflow: hidden; background: var(--code-background, rgb(30, 30, 30)); } .toc-accordion-title { cursor: pointer; padding: 1em 1.5em; font-weight: 600; font-size: 1.05em; background: var(--background, rgb(20, 20, 20)); color: var(--content-primary, rgb(218, 218, 218)); user-select: none; list-style: none; display: flex; align-items: center; transition: background 0.2s; } .toc-accordion-title::-webkit-details-marker { display: none; } .toc-accordion-title:before { content: '▶'; display: inline-block; margin-right: 0.7em; transition: transform 0.3s; font-size: 0.8em; color: var(--content-secondary, rgb(140, 140, 140)); } details[open] .toc-accordion-title:before { transform: rotate(90deg); } .toc-accordion-title:hover { background: rgba(255, 255, 255, 0.05); } .toc-accordion-content { padding: 1.5em; background: var(--code-background, rgb(30, 30, 30)); color: var(--content-primary, rgb(218, 218, 218)); } .toc-accordion-content nav > ul { list-style: none; padding-left: 0; margin: 0; } .toc-accordion-content ul { list-style: none; margin: 0; } .toc-accordion-content nav > ul > li { margin: 0.5em 0; } .toc-accordion-content li { margin: 0.3em 0; } .toc-accordion-content ul ul { padding-left: 1.5em; margin-top: 0.3em; } .toc-accordion-content a { color: var(--content-secondary, rgb(140, 140, 140)); text-decoration: none; transition: color 0.2s; display: inline-block; padding: 0.2em 0; } .toc-accordion-content a:hover { color: var(--content-primary, rgb(218, 218, 218)); } .toc-accordion-content nav > ul > li > a { font-weight: 500; color: var(--content-primary, rgb(218, 218, 218)); } html { scroll-behavior: smooth; } @media (max-width: 768px) { .toc-accordion { margin: 1.5em 0; } .toc-accordion-title { padding: 0.8em 1.2em; font-size: 1em; } .toc-accordion-content { padding: 1em; } .toc-accordion-content ul ul { padding-left: 1em; } } </style> <h2 class="heading" id="introduction"> Introduction <a class="anchor" href="#introduction">#</a> </h2> <p>When we talk about the Internet, it&rsquo;s so important that saying &ldquo;it&rsquo;s used like this, it&rsquo;s a must-have&rdquo; would sound too simple. We&rsquo;ll take a look at how the magic behind the internet actually works. What&rsquo;s happening in the background when you visit a webpage, send a message, or watch a video?</p>