Resolve Destination Net Unreachable - Ping Error Message

Welcome to the Network Engineering training section of CoreNetworkZ Tech Solutions. Today, I will explain one ping error response by the Command Prompt- Destination Net Unreachable.

This tutorial explains the meaning of the ICMP error message Destination Net Unreachable and teaches how to fix it.

Destination Net Unreachable is one of the common ICMP error messages you see when you ping a remote IP address as part of a ping test in network troubleshooting.

The first part of this tutorial explains why you receive Destination Net Unreachable error while pinging a web address. The second part of the tutorial teaches how to solve this error.

Dominic Monckton asked this question in the comments section. I am sure he is not alone. Many of my readers might be as curious as Dominic. This error message tells the ping request from your computer failed to find a route to the destination network.

Louise Barrett, one of our readers, saw this error while pinging Instagram from her laptop. She asked for the reasons in the comments section. Let me answer her in this section.

The ping packet couldn't find the destination network due to any one of the following reasons.

• Packet Routing issue.

• The destination network path might be down.

• An outdated Routing table on the default gateway without a route to the destination.

Martin Keneally asked for a technical explanation to present this topic for his college seminar. So, I have added this extra section to answer him.

When you ping an IP address from your computer, the ping packet goes to the default gateway.

The default gateway will check the destination address of the ping packet and find a route with the routing table entries.

The default gateway will send the ping packet to the destination address.

However, if the default gateway does not know the path to the desired network, your computer will get a Destination Net Unreachable message.

Let us examine the screenshot I uploaded below. I send ping packets to the global DNS address 4.2.2.2 from my computer.

However, the process went wrong and received the ping error Destination net unreachable on the command prompt.

I believe Martin Keneally is happy with this technical explanation. But, I am sure he and other readers wonder why my PC didn't receive the reply from 4.2.2.2.

Let me explain why I received the reply from the IP address 192.168.42.129 when I sent ping packets to 4.2.2.2.

Microsoft Windows [Version 6.1.7600]
Copyright (c) 2009 Microsoft Corporation.  All rights reserved.

C:\Users\sijugk>ping 4.2.2.2

Pinging 4.2.2.2 with 32 bytes of data:
Reply from 192.168.42.129: Destination net unreachable.
Reply from 192.168.42.129: Destination net unreachable.
Reply from 192.168.42.129: Destination net unreachable.
Reply from 192.168.42.129: Destination net unreachable.

Ping statistics for 4.2.2.2:
    Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),

C:\Users\sijugk>

Here I pinged the IP address 4.2.2.2 from my computer. The ping request went to the default gateway.

The default gateway in my network is a modem. The IP address of the modem is 192.168.42.129.

The modem failed to find a route to the destination network and replied to my computer with the Destination net unreachable message. Check this external reference to learn more about this error.

I explained the reasons for the ping error Destination Net Unreachable in the first part of this tutorial. Now, let us check how to fix this problem.

I recommend you follow the steps in the order provided below.

1. Power Cycle the Network:

   A proper power cycle will refresh the routing table entry and fix loose connection problems. Follow the instructions provided below carefully.

   
   

   • Switch off the devices on your network.

     
     

   • Disconnect power cables from Modem and Router.

     
     

   • Disconnect the Ethernet cables from Modem, Computer, and Router.

     
     

   • Reconnect the power and ethernet cables.

     
     

   • Power on the Router and wait till the power light is steady.

     
     

   • Power on the Modem and wait till the power light is steady.

     
     

   • Open Command Prompt and ping a website (for example- ping corenetworkz.com). If you still receive the same ICMP error, follow the next solution.

   I received many responses from my readers, including Stefano Terrile, mentioning the confirmation for this solution. You can read the response from Stefano in the comment section about how network power cycling helped him fix this issue.

   
   
   

2. Delete the Local Hosts Entries

   Third-party applications and malicious programs like viruses can rewrite the local host file on your Windows computer.

   
   

   A faulty entry on the local host file can prevent your Windows PC from accessing the Internet and results in Ping errors.

   
   

   Let us check how to fix the Destination Net Unreachable error on Windows computers by clearing the local host file.

   
   

   • Go to the location C:\Windows\System32\drivers\etc.

     
     

   • Right-click on the hosts and open in a Notepad.

     
     

   • Delete the entries and save the file.

     
     

   • Now ping a remote IP address and check for the issue.

   
   
   
   

3. Turn Off the Firewall

   Security Applications installed on your device can cause the ping error Destination Net Unreachable when you access the Internet over a VPN or Proxy. Allen Marshall confirmed it, and you can read his test results in the comment section.

   
   

   Turn off the firewall on your device to check whether the firewall was the reason for the error.

   
   

   To turn off the inbuilt Firewall on Windows 11 and Windows 10, follow the instructions.

   
   

   • Click on the Windows Start button.

     
     

   • Click Control Panel.

     
     

   • Click Windows Firewall.

     
     

   • Click the Turn Windows Firewall on or off option.

     
     

   • Click the Turn-off Windows Firewall radio buttons (both under the Private network settings and Public network settings) under the Customize Settings.

     
     

   • Click the OK button to save the settings.

Emilio Cereseto asked why his Linux laptop showed this ICMP error message. Let me answer him. ICMP error messages do not depend on the Operating System on your laptop.

I hope this tutorial helped you resolve Destination Net Unreachable ICMP Error on your computer.

CoreNetworkZ has many tutorials covering similar ICMP error messages. Some of them are below.

1. https://www.iana.org/assignments/icmp-parameters/icmp-parameters.xhtml
2. https://webstor.srmist.edu.in/web_assets/srm_ramapuram/files/internetcontrol.pdf