Error 651 – How to Fix Connection Failed With Error 651 in Windows

Error 651 needs no introduction; it simply defines itself on the error log window. However, what calls for attention is the need for users to understand what causes it. Error 651 is a Microsoft Windows problem that is largely related to the networking component of this widely used operating system. It’s bound to occur when you establish a dial-up connection to the server by using Integrated Services Digital Network (ISDN), and then you try to establish a virtual private network (VPN) connection. On other occurrences, it may be the result of upgrades and greatly relates to up-to-date network device drivers. The Error 651 is highly associated to the PPPoE(Point to Point Protocol Ethernet), controlling the computer’s communication and connection to the Ethernet. Therefore it is relatively true to say that this is local to the computer. Its cause can be linked to driving corruption, configuration or the entire Windows.


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Different Solutions To Fix Connection Failed With Error 651:

There is no universal solution for Error 651 but a basic outline of a few steps can lead us to a solution.

First to note; for any Windows related problem, opt for the troubleshooting option as recommended by Microsoft. In this case, troubleshoot error 651 by running the network troubleshooter. This saves your time and also provides you valuable information so you can understand the problem more deeply.

On the other hand, make sure that your modem or router through which you were establishing a connection, is working properly.

Now let’s head to some few of the fix it yourself steps you can adopt.

1.Check that your network card device drivers are up to date.

An up to date driver should establish a clear path for a successful connection to the network. Defined, a device driver is an interface between the computer and the device. It aids in communication and ensuring efficiency in establishing connections. They tell how your device should behave when connected to the computer. To check the status of your driver software follow these;

Navigate to Control Panel > System and Security > System within windows

  1. Select on Device Manager.
  2. Look for Network adapters  and then select on your card through which you are establishing a connection.
  3. Right click on the card and select Update driver software.
  4. Let Windows find a suitable driver software through a selection of the automatic option.

Windows may ascertain that you have up-to-date driver software. If this happens don’t stop there, remember we need a solution. Repeat step 3 but this time go for Browse my computer option and select the latest driver software obtained from the device manufacturer’s website and install it.

You can also carry a manual installation of the device driver through a .exe file.

2. Disable IPv6

In case the above seems not to counter the error 651, you can opt for this step. IPv6, an upgrade of IPv4, is basically a communication protocol that provides an identification and location system for computers on networks and routes traffic across the internet. What does it have to do with error 651? Its influence is based on it being the newest protocol and so it’s not in full use yet. Routers are having a hard task to incorporate and so it could be the root cause for your misconfiguration. It’s therefore advisable you turn it off until you entirely need it. To disable IPv6, follow the steps given below:

  1. Go to Start and open Control Panel.
  2. In Control Panel, click on Network & Internet and then choose Network & Sharing Center.
  3. Now click on your active network connection.
  4. From the pop up that opens, select Properties.
  5. From the options, untick Internet Protocol version 6 (TCP/IPv6)  and click Ok.


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3. Resetting your configuration.

In technical terms, I am asking you to reset TCP/IP on your Router or Modem. Type in the following in the CMD window run as administrator, hit enter and restart your PC.

 netsh int ip reset.log

4. Disable TCP auto-tuning.

First and foremost, TCP tuning is relevant when using many computers and since it’s a method for managing traffic on a network I don’t see its relevance when your network is a based on a single machine. Simply, a home network on average won’t require TCP tuning feature enabled. Also, remember that this solution can be carried on only when you are using a router.

To achieve this;

  1. Run CMD with administrative privileges (Win+X).
  2. Type in netsh int ip reset.log and hit Enter.
  3. Type netsh interface tcp set global autotuning=disabled and hit Enter.

You have disabled tcp tuning


I hope the above steps pushed you to a solution as they have worked for me. Always handle such errors appropriately, confirm that your ISP is not related to this else troubleshoot through the network troubleshooter to ascertain and get more clarity on the issue.

If you faced any type of problem after reading the above article carefully then you can surely leave your comments below in the comment box. If the article helped you solve error 651 problem, feel free to share it on social media.

Kenneth Malunga

Malunga is a Technology Education specialist from Kenya with focus on a global platform and the extensive desire for research in technology. He disseminates a range of product and process information with clarity and concision. Innovations in ICT are without doubt the most remarkable inventions of all times.

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