Ultimate Cable Internet Troubleshooting Guide (2021)

Fix problems with cable internet being slow, disconnecting, or not working.

Fix Cable Internet Connection Problems Kevin Jones / TechReviewer

Last Updated: September 10, 2021

Written by Kevin Jones

Work, entertainment, and communication can grind to a halt when your internet stops working. In this guide, I'll provide you with the knowledge to get your internet up and running again and give some tips for fixing common issues.

While I won't go into extensive detail about every possible configuration or cause of internet problems, as that would be near impossible, this guide will help you to understand your setup enough to determine how to proceed.

Suppose you want to try some quick solutions before you dive into this extensive troubleshooting guide. In that case, you can check out these guides for fixing simple internet problems for iPhone/iPad (TR), Android (TR), or Windows (TR). They also cover device-specific topics for when your internet is working on one device but not on another.

If you are initially wiring up your cable modem via a coax cable or want to optimize its signal levels and signal to noise ratio, check out my Ultimate Cable Internet Wiring & Optimization Guide (TR).

What Are the Key Components of Cable Internet?

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Many components make up a network, but you can conceptually think of them as just different parts of a system for passing around packets of data, providing you with access to the Internet. Whether the data flows over a coax cable, Ethernet cable, or wirelessly, the same information gets passed around (e.g., a website, email, or video).

Each home internet and network setup can vary. However, in my guide, Essential Equipment Guide for Cable Internet (TR), I provide an overview of the terms for common equipment. I'd highly recommend you check that out to familiarize yourself with what equipment your network is using.

How to Check Whether Your Internet Connection Is Working Properly

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The easiest way to check if your internet is working on Windows, Linux, or macOS is to run the following from the terminal or command prompt:

  ping google.com

For iOS or Android, you can find a "ping" tool via their respective app stores. They should work similarly to the command line versions.

This command will repeatedly send a packet to one of Google's servers and measure how long it takes to get a response (round-trip time).

If your connection problems are intermittent, you may want to run this multiple times or for a more extended period.

You want to look for any packet loss or timeout errors; either of these would indicate a problem. Ideally, the packet loss percentage should be at zero. Packet loss percentages are displayed when the command finishes or is stopped.

You can also evaluate whether the ping round-trip time is high. Usually, this should be in the low tens of milliseconds.

Is It a DNS Problem?

If you cannot ping google.com, it is worth verifying that it's not a DNS configuration problem.

You can verify this by pinging a well-known IP address such as google's DNS:

  ping 8.8.8.8

If this works, but pinging google.com doesn't, then it's likely a DNS problem.

If this is the case, check out our related articles which cover those topics:

How to Narrow Down the Cause of Internet Connection Issues

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If your connection problem isn't related to DNS (TR), we need to track down which component is causing the issue.

Like most technical problems, "divide and conquer" is a helpful strategy. Divide and conquer means to take one big problem—The Internet isn't Working!—and split it into small problems which are easier to solve. In this case, we'll use the Ping tool to identify which part of the communication with the internet isn't working.

1. Identify the Series of Devices Between Your Client and Your Cable Modem

Which series of devices are between your client device (phone/tablet/computer) and the coax cable? This list most commonly includes a router and a modem.

2. Ping Each Device, Starting With the Closest One

You may need to reference your device manuals or perhaps a sticker on the device to find the default IP address for the device.

Ping each device in the order in which they are connected, starting with the one to which your phone/tablet/computer is connected (e.g., Wi-Fi Router).

Device Common Default IP address
Router 192.168.1.1
Cable Modem 192.168.100.1

If those all work, you can also try pinging a popular website:

Website to try pinging
google.com
bing.com

3. Narrowing Down the Cause

If you can ping the router without packet loss, you know that your Ethernet cable or Wi-Fi connection is working. If you can ping the cable modem without packet loss, you know that everything up until the modem is working, including the cable between the router and modem.

Additionally, repeat the test from another client device to determine if the client device itself causes the problem.

Based on what you've discovered, go to the appropriate next section:

Next Steps
BehaviorNext Steps
Can only Ping from Some Clients (computers, phones, tablets, streaming devices)
Can't Ping Wireless (Wi-Fi) Router or Access Point from Any Device
Can't Ping Wired Router from Any Device
Can't Ping Modem
Can't Ping Website or IP

How to Fix Wired Client Connection Problems

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Possible causes and solutions:

  • Bad Cable: Replace the Ethernet cable (TR). Make sure to use Cat 6a or higher to achieve maximum speeds supported by your network.
  • Bad Client Network Adapter: If this is the only device experiencing this problem, it may be a client-side hardware failure. Replace the network adapter or device.
  • DHCP is Disabled: Ensure that your router and device have DHCP enabled to auto-assign IP addresses.
  • Router Crashed: Restart the router. The easiest way to do this is by removing the power for 10 seconds.
  • Bad Router Port: If some clients are not having connection problems, try switching to a different port. If a port has failed, try replacing the router.
  • Bad Client Device State: Restart the client device.
  • Outdated Router Firmware: Old firmware can often reduce speeds or cause other issues. You can update your firmware in the router's settings, usually found by going to 192.168.1.1 in your browser. You may need internet access in order to download new firmware, so you'll either need to fix other issues first or try to access your router via Wi-Fi.

Find Cat 6a Cables on Amazon (affiliate link).

Find Wi-Fi 6 Routers on Amazon (affiliate link).

How to Fix Wireless Client Connection Problems

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Possible causes and solutions:

  • Unsupported Wi-Fi Standard: If your client and router aren't configured for the same Wi-Fi standards (e.g., 802.11n, 802.11ac, 802.11ax), they won't communicate. Change the router configuration to match the client or replace the router or client to support the same standards. Newer devices are often backward compatible when configured correctly.
  • Unsupported Frequencies: If your client or router isn't able to support or configured to support the same frequencies (2.4 GHz, 5 GHz, 2.4/5 GHz), then they won't be able to communicate.
  • Bad Client Wi-Fi Adapter or Antenna: If this is the only device experiencing this problem, it may be a client-side hardware failure. Replace the device.
  • DHCP is Disabled: Ensure that your router and device have DHCP enabled to auto-assign IP addresses.
  • Router Crashed: Restart the router. The easiest way to do this is by removing the power for 10 seconds.
  • Bad Client Device State: Restart the client device.
  • Signal Interference: Try moving closer to the router. If this fixes the problem, then you may need to:
    • Remove obstacles that are blocking the signal.
    • Use the 2.4 GHz frequencies (rather than 5 GHz) to penetrate obstacles more easily.
    • Switch to a wired solution to avoid interference from neighbor devices.
    • Use a Wi-Fi Repeater/Extender (TR), Wi-Fi Access Point (TR), or a Wi-Fi Mesh System (TR) to distribute the signal better.
  • Outdated Router Firmware: Old firmware can often reduce speeds or cause other issues. You can update your firmware in the router's settings, usually found by going to 192.168.1.1 in your browser. You may need internet access in order to download new firmware, so you'll either need to fix other issues first or try to access your router via an Ethernet cable.

Find Wi-Fi Mesh Systems on Amazon (affiliate link).

Find Wi-Fi Access Points on Amazon (affiliate link).

Find Wi-Fi Extenders on Amazon (affiliate link).

Find Wi-Fi 6 Routers on Amazon (affiliate link).

How to Fix Unreachable Wi-Fi Router and Access Point Problems

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Possible causes and solutions:

  • DHCP is Disabled: Ensure that your router and device have DHCP enabled to auto-assign IP addresses.
  • Router Crashed: Restart the router. The easiest way to do this is by removing the power for 10 seconds.
  • Bad Router: Consumer routers often fail after a few years. Try replacing the router.
  • Signal Interference: Try moving closer to the router. If this fixes the problem, then you may need to:
    • Remove obstacles that are blocking the signal.
    • Use the 2.4 GHz frequencies (rather than 5 GHz) to penetrate obstacles more easily.
    • Switch to a wired solution to avoid interference from neighbor devices.
    • Use a Wi-Fi Repeater/Extender (TR), Wi-Fi Access Point (TR), or a Wi-Fi Mesh System (TR) to distribute the signal better.
  • Bad Config: Old settings may be conflicting with an automated or manual firmware updated, or the configuration may have become corrupt. Do a factory reset by holding the reset button with a pin.
  • Outdated Router Firmware: Old firmware can often reduce speeds or cause other issues. You can update your firmware in the router's settings, usually found by going to 192.168.1.1 in your browser. You may need internet access in order to download new firmware, so you'll either need to fix other issues first or try to access your router via an Ethernet cable.

Find Wi-Fi Mesh Systems on Amazon (affiliate link).

Find Wi-Fi Access Points on Amazon (affiliate link).

Find Wi-Fi Extenders on Amazon (affiliate link).

Find Wi-Fi 6 Routers on Amazon (affiliate link).

How to Fix Unreachable Wired Router Problems

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Possible causes and solutions:

  • Bad Cable: Replace the Ethernet cable (TR). Make sure to use Cat 6a or higher to achieve maximum speeds supported by your network.
  • Bad Client Network Adapter: If this is the only device experiencing this problem, it may be a client-side hardware failure. Replace the network adapter or device.
  • DHCP is Disabled: Ensure that your router and device have DHCP enabled to auto-assign IP addresses.
  • Router Crashed: Restart the router. The easiest way to do this is by removing the power for 10 seconds.
  • Bad Router: Consumer routers often fail after a few years. Try replacing the router.
  • Outdated Router Firmware: Old firmware can often reduce speeds or cause other issues. You can update your firmware in the router's settings, usually found by going to 192.168.1.1 in your browser. You may need internet access in order to download new firmware, so you'll either need to fix other issues first or try to access your router via Wi-Fi.

Find Cat 6a Cables on Amazon (affiliate link).

Find Wi-Fi 6 Routers on Amazon (affiliate link).

How to Fix Network Cable Problems

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You can easily replace network cables with an equivalent or faster one.

Ensure that network cables are labeled based on the speeds that you expect and your equipment.

Cat 6 or Cat 6a is my recommendation for new in-wall installations and future-proofing, as it's fast but less flexible than Cat 5e.

Cat 5e is my recommendation for in-room usage due to its increased flexibility.

For more details on which speeds each Ethernet cable type supports, check out the Types of Ethernet Cables (TR) section of my Ultimate Cable Internet Wiring & Optimization Guide (TR).

Find Cat 6a Cables on Amazon (affiliate link).

How to Fix Network Switch and Hub Problems

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Most passive network switches and hubs aren't ping-able, but you'll know if something is wrong if you can fix the problem by bypassing the device.

Possible causes and solutions:

  • Wrong Cable Type: Most newer devices will auto-switch to work with both crossover and straight-through cables. However, you'll need to use the appropriate type for older devices or devices that don't auto-switch. The general strategy is to use a straight-through cable for devices of different types (e.g., computer to network switch) and crossover cables for same-type devices (e.g., connecting two computers or two switches).
  • Bad Cable: Replace the Ethernet cable (TR). Make sure to use Cat 6a or higher to achieve maximum speeds supported by your network.
  • Bad Switch/Hub: Try bypassing or replacing the switch or hub.

How to Fix Unreachable Cable Modem Problems

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  • Modem Crashed: Restart the modem. The easiest way to do this is by removing the power for 10 seconds.
  • Bad Config: Old settings may be conflicting with an automated or manual firmware updated, or the configuration may have become corrupt. Do a factory reset by holding the reset button with a pin.

How to Fix Internet Connection and Coax Cable Problems

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I discuss the various considerations when setting up coax cables and optimizing signal levels and signal-to-noise ratios in my Ultimate Cable Internet Wiring & Optimization Guide (TR).

As discussed in that article, here are some possible causes and solutions:

  • High/Low Signal Level: To decrease levels, add attenuators. To increase levels, reduce cable length, remove splitters or attenuators, or add an amplifier.
  • High SNR: Add terminators to ends of unused coax cable and splitter ports, disconnect unused coax cables, remove other devices communicating over the cable (MoCA adapters/DVRs), add MoCA POE filters, replace splitters with attenuators if possible, ensure coax wiring and connectors are high quality (RG-6 cable with F-Connector Compression Fitting).
  • Bad Coax: Coax wiring with poor shielding or connectors may cause problems. Ensure coax wiring and connectors are high quality (RG-6 cable with F-Connector Compression Fitting).
  • Bad Coax Components: Try bypassing components to determine if they've failed. For example, MoCA POE filters may fail, causing connection problems.
  • DHCP is Disabled: If you connect a computer directly to a modem that doesn't have a built-in router, ensure that your computer has DHCP enabled. If you use a router for distributing internet from your modem, ensure that the router is configured to acquire an IP address from your ISP dynamically.

How to Fix Upstream Internet Service Provider Problems

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If you've exhausted all possible coax setup considerations, contact your internet service provider to send out a technician. They may need to fix or adjust devices you don't have access to.