When using a high-speed PPPoE connection, it is often possible to observe a connection failure with error 651, at which a corresponding notification is issued, somewhat reminiscent of a similar message about mini-port problems and error 678. Some users immediately begin to feverishly reinstall the operating system, although there is a clear need for this is not. Correcting this situation, unless it is connected with the provider or operator that provides communication services, or the breakdown of network equipment, can be quite simple. Consider some of the most common causes of this phenomenon and methods that allow you to resolve problems.
Causes of a connection failure with error 651
If we talk about the possible causes of this phenomenon, then they are mainly associated with incorrect installation of network parameters or problems in the operation of the main equipment. We will not dwell on damage to routers, modems, or connecting network cables, but we will pay more attention to the parameters set for a high-speed connection. It is worth paying attention to the fact that the appearance of a failure with error 651, as in the case of problem 678, does not affect device drivers, although it goes without saying that they must be installed correctly. Most often, the situation is associated with conflicts that can be triggered by the use of several network cards, each of which has its own connection. Sometimes a 651 connection error may also be generated due to incorrectly set parameters of the routers themselves or network protocols. By the way, blocking the connection of various kinds of antivirus programs or firewalls cannot be excluded either. The rarest cases are situations involving corruption of the registry and the presence or absence of the necessary keys in it (we will dwell on this separately).
The modem reported error 651: actions with network connections
First, see how many network cards you have installed. It may well be that it is precisely this fact that influences the appearance of connection error 651, when the system cannot figure out which one to make the connection through. In this case, the easiest solution is to disable one of the adapters, which can be done in the standard "Device Manager".
Alternatively, you can fix the connection failure with error 651 by creating a new network connection with the mandatory (!) Deleting the existing one, since without this the system can simply inherit some settings that are usually written not even in the protocol parameters, but in the registry, which will lead to repeated the occurrence of conflicts. In this situation, you just need to correctly enter all the parameters that, when concluding the contract for the provision of Internet access services, are indicated by the operator or provider. Please note that when connecting through a router, it must be configured in Bridge mode. Without this, the described actions simply will not make any sense.
Reset or change router settings
It is believed that no less than 651 error when connecting to the Internet, if it appears even when the connection is recreated, it is eliminated by resetting all router settings.
However, it is recommended to perform such actions not by turning off the power, but directly in the interface of the devices themselves with re-setting the necessary options and parameters at the end.
Registry Actions
As for the system registry, there are some peculiarities, since its incorrect parameters can cause both the described failure and error 800, if using wireless mode. In the editor (regedit) you must use the HKLM branch. In it, through the system folder and directories of the current control settings and services, go to the Tcpip directory, in which there is a section for parameters (Parameters). Here you need to pay attention to two keys - EnableRSS and DisableTaskOffload. For the first, the value is set in the form of zero, for the second - one.
If there are no such keys, DWORD parameters with the specified names will need to be created independently and assigned appropriate values. At the end of all the steps, a complete restart of the computer will be required.
Antiviruses and firewalls
Finally, a connection failure with an error of 651, as in many similar cases, can occur when blocking the created or used connection with all kinds of security programs, including even regular antiviruses and the built-in firewall of the operating system.
As already, probably, it’s clear that they should be disconnected at least temporarily, check the connection, and when identifying its working state, use the inclusion in the exclusion list. But usually you can do even easier by changing the same free antivirus to a more powerful program. This is most often observed in the case of installing the free Avast package, for which such "wayward" behavior is noticed.