Why Is My Internet Slow? A Complete Troubleshooting Guide

After helping thousands of customers troubleshoot internet connectivity issues over my 12 years as a network engineer, I can confidently say that most slow internet problems have simple solutions. You don’t need to be technically savvy to fix them—you just need to know where to look. Last week alone, I helped three neighbors solve their “terrible internet” problems, and in each case, the fix took less than 10 minutes. This guide walks you through the exact troubleshooting process I use to identify and resolve slow internet issues, from the simplest fixes to more complex solutions.

Network Troubleshooting with tcpdump and Wireshark

Network troubleshooting is an essential skill for system administrators, DevOps engineers, and security professionals. When applications fail or perform poorly, packet-level analysis often reveals the root cause. This comprehensive guide explores tcpdump and Wireshark, the industry-standard tools for capturing and analyzing network traffic.

Understanding Packet Capture

Packet capture operates at the network interface level, intercepting all traffic passing through. Both tcpdump and Wireshark use libpcap (or WinPcap/Npcap on Windows), which provides a portable framework for low-level network monitoring^[1].