Packet loss troubleshooting: how to diagnose and fix it

What is packet loss and why does it happen?

When you use the internet, information travels between your device and remote servers in small units called packets. These packets carry the data needed to load websites, send messages, stream videos, and communicate with other devices.

Packet loss occurs when some of these packets fail to reach their destination.

For example, imagine your device sends 100 packets to a server. If 5 packets never arrive, the observed packet loss is 5%.

The missing information may need to be retransmitted, depending on the network protocol and application. This can increase delays, interrupt real-time communication, or reduce the effective performance of a connection.

Packet loss can occur at different points:

• Between your device and Wi-Fi router.
• Between your router and modem or access equipment.
• Across your ISP's network.
• Along an intermediate network route.
• Near the destination server.

Key fact: Packet loss does not automatically mean your internet subscription is too slow. A connection can have substantial download speed but still perform poorly because of unstable connectivity or lost packets.

What are the signs of packet loss?

Packet loss can affect different online activities in different ways. Its impact depends on how frequently packets are lost, where the loss occurs, and how the application handles missing data.

Common warning signs include:

These symptoms are not proof of packet loss. High latency, insufficient bandwidth, server problems, and device performance can produce similar experiences.

Key tip: Pay attention to when the problem occurs. If your connection becomes unstable when several devices are active, investigate network congestion as well as packet loss.

What causes packet loss?

Understanding the possible cause is important because different problems require different solutions.

Weak Wi-Fi signal and wireless interference

A weak wireless signal can make communication between your device and router unreliable.

Distance, walls, floors, metal objects, and interference from other wireless equipment can affect Wi-Fi performance.

For example, a laptop several rooms away from a router may experience an unstable connection even when a smartphone beside the router works normally.

Apple's Wi-Fi interference troubleshooting guidance explains how interference and physical obstructions can contribute to poor wireless performance.

Network congestion and router overload

Network congestion happens when available network capacity is insufficient for the traffic being transmitted.

This can happen when multiple devices simultaneously download large files, stream high-resolution video, upload backups, or participate in video conferences.

An overloaded router may also struggle to process traffic efficiently, especially if it has limited hardware resources or is running poorly.

However, congestion does not always produce packet loss. It can also cause increased latency without measurable loss.

Faulty Ethernet cables and network hardware

Physical network problems can interrupt data transmission.

Potential causes include:

• Damaged or poorly terminated Ethernet cables.
• Loose cable connections.
• Defective router or modem ports.
• Faulty switches.
• Unstable power adapters.
• Overheating network equipment.

A cable can appear connected while still producing intermittent connectivity problems.

ISP and network routing problems

Your internet provider connects your local network to other networks and internet destinations.

Problems with ISP equipment, overloaded links, routing changes, or upstream network connections can cause intermittent packet loss.

This is particularly worth investigating when multiple devices experience the same issue over both wired and wireless connections.

Firewall, VPN and software issues

Network security software, VPN connections, firewalls, and traffic-management applications can affect how network traffic is processed.

A VPN adds another network path between your device and the destination. If the VPN connection or its route is unstable, applications may experience delays or connection interruptions.

Similarly, incorrectly configured firewall rules or security software can block or disrupt certain traffic.

Do not assume these applications are responsible simply because they are installed. Compare results carefully before changing their settings.

How to check whether your internet has packet loss

Before changing router settings or contacting your ISP, collect some evidence.

There are several ways to investigate packet loss, including browser-based checks, command-line ping tests, and network route diagnostics.

1. Run a packet loss test

Start with a browser-based packet loss check.

Open the packet loss test and run the available measurement.

Pay attention to:

• Whether all measurement requests complete successfully.
• Whether some requests fail or time out.
• Whether the problem appears consistently across repeated tests.
• Whether the results change when you use another network.

Important measurement limitation: A browser-based test measures failures in its own HTTP measurement requests. It does not directly measure UDP or ICMP packet loss at the network layer.

A failed HTTP request may result from several issues, including connection interruptions, server-side problems, or browser/network errors. It should be treated as a diagnostic clue rather than definitive proof of network-layer packet loss.

For a more complete investigation, use operating-system network tools as well.

2. Test your connection using ping

Ping sends small network probes to a destination and measures whether replies return.

You can use it to check whether your device can communicate consistently with a reachable server.

On Windows:

1. Press Windows + R.
2. Type cmd and press Enter.
3. Enter the following command:

ping -n 50 1.1.1.1

4. Press Enter.
5. Allow the test to complete.
6. Review the packet statistics.

On macOS or Linux:

Open Terminal and run:

ping -c 50 1.1.1.1

The output generally includes:

• Packets transmitted.
• Packets received.
• Packet loss percentage.
• Minimum response time.
• Average response time.
• Maximum response time.

For example, if 50 packets are sent and 48 replies are received, the reported unanswered-probe rate is 4%.

Repeat the test using another reliable destination to compare results.

Important: A missing ICMP reply does not always indicate that a packet was lost while being forwarded. Some routers and destinations limit or deprioritize diagnostic responses. Compare multiple destinations and use other evidence before identifying a fault.

3. Test your local router

Testing your router can help determine whether the problem is happening inside your local network.

First, identify your default gateway.

On Windows, run:

ipconfig

Find the Default Gateway address under your active network adapter.

For example, your router might use 192.168.1.1, but the actual address depends on your network configuration.

Now run:

ping -n 50 192.168.1.1

Replace the example address with your actual default gateway.

On macOS and Linux, use:

ping -c 50 192.168.1.1

Compare the results with your test to an external destination.

If the gateway test shows missing replies, investigate the device-to-router connection, Wi-Fi signal, Ethernet cable, and router.

Remember that some routers deprioritize ICMP responses, so repeated results and other observations matter.

4. Trace where packets may be getting lost

A ping test can reveal that communication is unreliable, but it does not show the entire route between your device and a destination.

Traceroute-based tools help investigate intermediate network hops.

On Windows:

tracert 1.1.1.1

For additional packet-loss statistics, use:

pathping 1.1.1.1

On macOS or Linux:

traceroute 1.1.1.1

You can also use MTR, where available:

mtr -rw -c 100 1.1.1.1

Traceroute displays the route taken by probes, while MTR combines route discovery with repeated measurements.

Windows pathping gathers statistics over time to help investigate loss at intermediate hops. See Microsoft's official pathping documentation.

Cloudflare also recommends traceroute and MTR for investigating network-path problems. Its network troubleshooting documentation explains when these tools are useful.

Do not mistake an intermediate-hop timeout for confirmed end-to-end packet loss. A router may simply decline to respond to diagnostic probes while continuing to forward traffic normally.

Look for loss that continues through subsequent hops and affects the final destination.

How to fix packet loss: step-by-step

Once you have collected some diagnostic evidence, work through the following solutions.

Start with the simplest checks and repeat your tests after each meaningful change.

1. Restart your modem and router

Restarting network equipment can resolve temporary software or connection problems.

Follow this process:

1. Save any important work and make sure no firmware update is in progress.
2. Turn off your router.
3. Turn off your separate modem or fibre access equipment, if applicable.
4. Wait approximately 30 seconds.
5. Turn the modem or access equipment back on.
6. Allow it to reconnect fully.
7. Turn on the router.
8. Reconnect your devices and repeat your tests.

Some internet services use combined modem-router equipment, so you may only need to restart one device.

Restarting is not the same as performing a factory reset. Do not press and hold the reset button unless you intentionally want to erase the device's configuration.

2. Switch from Wi-Fi to Ethernet

A wired connection removes the wireless link between your device and router from the test.

Connect your computer directly to the router using a working Ethernet cable.

Run the same ping or other diagnostic tests again.

Compare the results:

• If the wired connection works normally but Wi-Fi does not, investigate wireless signal quality and interference.
• If both connections show similar problems, investigate the router, access equipment, ISP, and wider network path.

This is one of the most useful ways to isolate a wireless problem from a wider connectivity issue.

3. Improve your Wi-Fi signal

If packet loss or disconnections appear only on Wi-Fi, improve the wireless environment.

Try these adjustments:

• Move closer to the router.
• Place the router in a central, elevated location.
• Keep it away from large metal objects and enclosed spaces.
• Avoid placing it beside microwave ovens and other potential sources of interference.
• Experiment with a different Wi-Fi channel if neighbouring networks are congested.
• Try the 5 GHz band when your device is close enough to benefit from it.

The 2.4 GHz band generally offers better reach through obstacles, while 5 GHz can provide more available bandwidth and less interference in some environments.

Actual performance depends on your router, device, surroundings, and Wi-Fi configuration.

4. Reduce network congestion

If your connection becomes unstable when several people use the internet simultaneously, check how bandwidth is being consumed.

For example:

• Pause large downloads temporarily.
• Schedule cloud backups outside busy hours.
• Reduce unnecessary simultaneous video streams.
• Check whether devices are uploading large files.
• Review traffic-heavy applications and connected devices.

Repeat the tests when the network is quiet.

If the connection performs normally with fewer active devices, investigate congestion or router processing limitations.

5. Check Ethernet cables and network equipment

Inspect the physical connections between your computer, router, modem, and any network switches.

Check for:

• Loose connectors.
• Damaged cables.
• Bent cable clips.
• Unusual heating.
• Damaged Ethernet ports.

Try another known-working Ethernet cable.

You can also switch to another available LAN port to see whether the problem changes.

Do not replace every piece of equipment immediately. Test one component at a time so you can identify which change makes a difference.

6. Update network drivers and router firmware

Outdated or problematic network software can contribute to connectivity issues.

For computers:

1. Open your operating system's update settings.
2. Check for available updates.
3. Review network adapter updates.
4. Use the computer or network adapter manufacturer's official support resources if needed.

For routers:

1. Identify the router's exact model.
2. Open its official administration interface.
3. Check whether an updated firmware version is available.
4. Follow the manufacturer's installation instructions.
5. Avoid interrupting the update process.

Back up your router configuration where supported before making significant firmware changes.

Never install firmware intended for a different router model.

7. Check VPN, firewall and security software

Temporarily compare your connection with and without a VPN, provided your usage and security requirements allow it.

If you notice a consistent difference:

• Check the VPN server location.
• Try another VPN endpoint.
• Check whether the VPN application is updated.
• Review firewall rules and security software logs.

Do not permanently disable your firewall or antivirus protection as a troubleshooting shortcut.

For business or managed networks, consult the network administrator before changing security settings.

8. Contact your internet service provider

If the problem continues across multiple devices and both wired and wireless connections, contact your ISP.

Ask the provider to investigate:

• Connection interruptions.
• Modem or optical network terminal signal levels.
• Line errors.
• Local access-network congestion.
• Router or access equipment faults.
• Routing problems, where appropriate.

Give the support team your diagnostic results rather than simply reporting that the internet is slow.

This makes it easier to distinguish a local network problem from a provider-side issue.

How to identify where packet loss is happening

Your test results can help narrow down the location of the problem.

The following table provides practical diagnostic clues.

These observations are not definitive diagnoses. Use repeated tests and multiple destinations before deciding where the problem originates.

Key tip: Keep a record of your test results before and after each change. This makes it easier to identify whether a troubleshooting step actually improved the connection.

How packet loss affects gaming, streaming and video calls

Not every application responds to packet loss in the same way.

Online gaming

Real-time online games depend on continuous communication between the game client and server.

When relevant packets are delayed or lost, players may experience:

• Rubber-banding.
• Delayed actions.
• Unexpected movements.
• Interrupted gameplay.
• Temporary disconnections.

Some games can compensate for occasional missing updates, but repeated or poorly timed loss can make gameplay unreliable.

For a separate latency check, use the gaming ping test.

Video streaming

Streaming platforms often use buffering and adaptive video quality to manage changing network conditions.

However, recurring connection problems can interrupt data delivery and contribute to buffering or playback interruptions.

A slow internet connection is not the only possible explanation. Network congestion, server problems, and insufficient available bandwidth can produce similar symptoms.

Video calls

Video calls are especially sensitive to inconsistent real-time communication.

Packet loss can contribute to:

• Missing audio.
• Robotic or distorted speech.
• Frozen video.
• Delayed communication.

Google's Meet troubleshooting guidance recommends checking network performance and trying a wired Ethernet connection when video or audio quality is poor.

When should you contact your ISP?

Consider contacting your provider when:

• Packet loss continues after basic local troubleshooting.
• Multiple devices experience the same connection problems.
• Both Wi-Fi and Ethernet connections are affected.
• Your connection regularly disconnects.
• The problem appears at particular times of the day.
• Diagnostic results suggest a potential problem beyond your local network.

Before contacting support, prepare the following information:

Ask the provider to check the line, access equipment, and network connection.

Keep your original diagnostic results so you can compare them with the provider's findings.

Final thoughts

Packet loss can make a fast internet connection feel unreliable, but the solution depends on finding where the problem starts.

Begin by testing your connection, checking your local gateway, and comparing Wi-Fi with Ethernet. Then investigate the router, cables, network software, and ISP connection as needed.

Avoid making several changes at once. Test after each adjustment so you can identify what actually improves your connection.

Ready to investigate your connection? Start with our packet loss test and use the additional troubleshooting methods in this guide to understand your results.