Team CoreNetworkZ explained various ICMP error messages in this blog.
Today we discuss one of the ICMP error replies when we ping a remote device from our computers, Destination Port Unreachable message.
You will learn the meaning and solution for this ICMP Port Unreachable reply.
Let us first check when we get this ICMP Reply Destination Port Unreachable.
We will get this error while pinging a remote device or server from our PC.
This tutorial discusses the reasons for getting the ICMP error Destination Unreachable (Port Unreachable) and explains how to resolve this issue.
At first, we check the meaning of the ICMP Error Reply Destination Port Unreachable.
What Does Destination Unreachable (Port Unreachable) Mean?
The Destination Port Unreachable error tells us that the ping packet we sent failed to reach the desired destination and dropped.
Let me explain this with a real-world example. When someone pings a remote host, the ping packets will travel from his device to the destination.
Ping packets will reach the destination gateway, and the remote router redirects them to the exact host.
If the host is too busy or the device port does not support the type of packets we send, it will result in the reply Destination Port Unreachable.
It tells us the problem lies with the host, and the network route (up to the remote host) works fine.
So, this reply is from the host (not from the remote gateway) and different from the following ICMP replies.
Destination Host Unreachable Error
Ping Error Reply- Request Timed Out
PING: Transmit failed. General Failure
One of our readers asked whether a Linux system will show the Destination Unreachable ( Port Unreachable) error.
Destination Port Unreachable ICMP reply is independent of the Operating System platform.
Both the Windows and Linux PCs display this ICMP reply.
Now we check why a PC shows Destination Unreachable (Port Unreachable) Ping Reply.
Reasons for Getting Destination Port Unreachable Error
The following reasons will cause the ICMP Reply Destination Port Unreachable.
Unaccepted Protocol Type-
One of the main reasons for the Port Unreachable error is sending packets to a remote host without the required protocol to be accepted by the active port of the remote host.
Remote Port is Busy-
If the port is busy while the ping packets reach, the chances of getting a rejection are very high. It may also result in the ICMP reply from the remote host on the sender with the message Destination Unreachable (Port Unreachable).
Possible Ban on Sender IP Address
Another reason is the possible ban on the sender IP address configured at the remote host. Remote Port will reject packets sent from a banned address.
Remote Router Firewall Settings Changes Packets Encapsulation
Our study shows the Remote Host Firewall (rarely) causes Destination Unreachable (Port Unreachable) error.
To test it, we should ask the remote host admin to turn off the firewall (if you have such a privilege).
Remote Port Might be Damaged
If the remote port is damaged, you may receive a Destination Port Unreachable reply on your computer.
You have learned why your PC shows the Ping Destination Unreachable (Port Unreachable) message. Let us check the steps to fix it.
How to Fix Destination Port Unreachable Error?
Troubleshooting the ICMP Port Unreachable error is a bit difficult because the issue lies with the remote device.
This error reply is due to a protocol mismatch or security issues mostly.
If you see the ICMP reply Destination Unreachable (Port Unreachable), follow the steps below.
Ping a Different Address
When you see ICMP Destination Unreachable message, ping a different IP address or web URL.
For example, if you receive the ICMP reply Port Unreacbale when you ping https:www.corenetworkz.com, try to ping https://www.google.com.
If you get packet-received messages from the destination, you can verify the source of the problem.
Ping the Address From a Different IP address
Ping packets from a banned IP will result in ICMP Port Unreachable Error.
Ping the Remote IP (or hostname) from a different IP address to verify it.
Disable the Proxy and VPN Services
Turn Off the Proxy and VPN services on your device and ping the remote server again.
Occasionally Proxy networks cause the ICMP Destination Unreacbahle (Port Unreachable) error.
You can resolve it by turning off the VPN.
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Check for Protocol Mismatch
ICMP requests do not use a port number, but TCP and UDP packets use port numbers.
Theoretically, a Port Unreachable message comes with UDP and TCP connection failure.
Destination Port Unreachable reply should not be from ICMP echo requests.
Other Important ICMP Replies
Ping Gives Hardware Error - Reasons And Resolution
How to Convert D-Link Wireless Router into Bridge M
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CoreNetworkZ.com has a collection of useful articles like how to open a port in Cox Modem and how to fix Acer Laptop hanging issues.
Wonderful guide. Thanks you helped me.
ReplyDeleteI am glad to know this guide helped you.
ReplyDeleteI faced this port unreachable error on my company. I spent a lot of time to solve it. It was the problem with the Network Interface Card on the Linux system in the second network. Finally figured it out.
ReplyDeleteThanks for this post.
Thank you for sharing your experience.
ReplyDeleteDoesn't a system restore fix this error?
ReplyDelete@ Unknown
ReplyDeleteThe chances are very very rare.
Good narration. Congrats
ReplyDelete@ Unknown
ReplyDeleteThank you for your appreciation.