How to Solve a Destination Host Unreachable Error

Receiving a “destination host unreachable” error in a Command Prompt network ping test can be frustrating. As you can see from the details below, we're trying to ping a specific network device IP address, but the response we're getting doesn't provide much detail beyond the error itself:

C:\Users\Me>ping 151.101.194.114
Pinging 151.101.194.114 with 64 bytes of data:
Reply from 151.101.194.114: Destination host unreachable.
Reply from 151.101.194.114: Destination host unreachable.
Reply from 151.101.194.114: Destination host unreachable.
Reply from 151.101.194.114: Destination host unreachable.

So, what's going on here? In simple terms, we're trying to communicate with a device at the specified IP address, but the remote gateway is unable to direct our ping request to the host itself, and so it sends an echo message back to say that it can't be found.

This guide focuses on local networking issues for Windows devices.

Cause of a Destination Host Unreachable Error

There are many possible reasons for getting a “destination host unreachable” error, including things as simple as erroneously connected cables or an overly aggressive firewall. With this in mind, it’s useful to follow these steps to fix an IPv6 error first to see if they resolve your networking issues.

If the problem persists, you need to look at your network infrastructure to establish where the issue is.

How to Fix a Destination Host Unreachable Error

For this example, we’re going to check our Default Gateway settings, then follow the steps to fix them.

To start, we need to check our internet connection via a browser. For this example, we'll check google.com to see if it loads on our device. If it does, we know there's a problem on our local network, rather than a broader connection issue.
Next, we're going to test our IPv6 connection to see if that's where the issue lies. To do this, open the Command Prompt and use the following command to ping your original IP address, but type "ping -6" to isolate the IPv6 line.
```
C:\Users\Me>ping -6 151.101.194.114
```

You should get a reply in the Command Prompt, which looks like this:

Pinging 151.101.194.114 with 64 bytes of data:
Reply from 151.101.194.1.241: Destination host unreachable.
Reply from 151.101.194.1.241: Destination host unreachable.
Reply from 151.101.194.1.241: Destination host unreachable.
Reply from 151.101.194.1.241: Destination host unreachable.

The above reply comes from IP address 151.101.194.1.241, which seems to relate to the remote gateway handling our request. To check this, run a traceroute using the following command:
```
C:\Users\Me>tracert -6 -d 151.101.194.114
```

You should get a response, and it should resemble the following:

Tracing route 151.101.194.114 over a maximum of 30 hops:
1 1 ms 1 ms 1 ms 151.101.194.1.241
2 151.101.194.1.241 reports: Destination host unreachable.
Trace complete.

From this we can make a judgement that 151.101.194.1.241 is configured as the default gateway. To check if this is as it should be, we can look at our IP settings via the netshell. To launch netshell, enter the following command:
```
C:\Users\Me>netsh
```

With netshell open, enter this command:

netshell>interface ipv6
netshell interface ipv6>showconfig

The response will show our Local Area Connection details, with a reference line for the Default Gateway. In our example we see the following:

Default Gateway 151.101.194.1.241

This confirms that 151.101.194.1.241 is currently configured as the default gateway, but when we look at our actual device's IP address, we see it's slightly different: 151.101.194.1.244.

How to Add the Correct Gateway Address for a Destination a Host

From the information gained above we can see we need to add the correct gateway address via our Local Area Network (LAN) settings. To do this, follow these steps.

Select Settings > Network and Internet > Network Connections.
Right-click the relevant Local Area Network, then select Properties.
From the list, select Internet Protocol Version 6 (TCP/IPv6), then select Properties.
In the Properties tab, change the Default Gateway to the correct address. So, in this example we change "151.101.194.1.241" to "151.101.194.1.244."
Select OK to save the changes.

How to Check if Destination a Host Unreachable Error is Resolved

To check if the issue is resolved, go back to the Command Prompt and exit the netshell using the following command:
```
netsh interface ipv6>exit
```
Now we're ready to try our ping test once more, using this command:
```
C:\Users\Me>ping -6 151.101.194.114
```

Just as before, the ping should come back with a reply showing the new Default Gateway.

Pinging 151.101.194.114 with 64 bytes of data:
64 bytes from 151.101.194.114: icmp_seq=0 ttl=57 time=27.205 ms
64 bytes from 151.101.194.114: icmp_seq=1 ttl=57 time=14.109 ms
64 bytes from 151.101.194.114: icmp_seq=2 ttl=57 time=13.887 ms
64 bytes from 151.101.194.114: icmp_seq=3 ttl=57 time=13.954 ms
64 bytes from 151.101.194.114: icmp_seq=4 ttl=57 time=18.269 ms