What happens when a computer suddenly fails to connect to the net? Computer suddenly unable to online solution

Solution:

1. Internet access via dial-up
If you are connecting to the network by dialing, click here to find out the cause of the problem.
2. Connect by wireless means
1 Check the status of the wireless signal to confirm the signal is normal. Wireless signal icon in your lower right corner of the taskbar, such as wireless signal is not good, please move to the wireless router near the location of the test, so that the Red Fork status, please confirm that the wireless network card driver is normal, you can open the Device Manager to view;

2 Confirm whether you can search for wireless networks that need to be connected;

3 If you can not search, please confirm that your wireless router has turned on the broadcast function, such as you can not confirm, please contact the administrator to handle, or through other computers to obtain the corresponding network name, for manual connection;

4 Please confirm the wireless password input is normal, wireless password access please contact the network administrator;

5 after connecting to the wireless network, please confirm whether you need to manually set the IP address;

6 in the routing settings may have a MAC address and IP address binding relationship, please contact the administrator to confirm;

7 Finally, we suggest that you can restart the routing test if it is convenient;

8 Download the wireless network card driver, try to reinstall the wireless network card driver test again.

3. Connect over a wired network but not a dial-up connection

1 Check Device Manager, device driver, etc. is normal, such as in the "network adapter" has unknown equipment, please download the corresponding network card driver, to install;

2 first check the state of the local connection, such as the display of the broken state, please check whether the local connection is disabled, such as deactivated, please open the test.

3 If the above problems can not be resolved, please check whether the network cable is normal, if you can try to replace the network cable, or other computers on the network cable directly replaced to this host test, if still ineffective, the cause of this problem is generally hardware-led;

4 If the connection is normal, the network appears to be restricted state, then confirm that other computers are connected to normal, such as other computers are also unable to connect, this problem to determine the cause of the network environment, the problem does not appear in computer products, please check the network problem;

5 if the elimination of network problems, please confirm that the network needs to carry out a fixed IP address to the Internet, please try to manually specify the IP address of the way to test;

6 If the above solution can not solve your problem, please try to download the corresponding model of the network card driver, the installation of network card driver after the test is normal.

Can not surf the internet may also be the problem of DNS (ADSL dial-up access error code detailed)

Summarize:
Encounter 678 common Solution ideas and steps:

1, the first confirmation of ADSL modem dial-up Normal, because the network card automatically acquired IP is not clear, so again when the network card can not get new IP address will be prompted 678, the operating method is: off the ADSL modem, access to the control Panel of the network connection right click the local connection selection disabled, After 5 seconds right click on the local connection select Enable, and then open the ADSL modem dial;
2, if the first step is invalid, then the ADSL modem in the case, still disable the local connection (network card), restart the computer, and then enable the local connection (network card), and then open ADSL modem can be resolved;
3, if the above steps can not be resolved, to see whether the network card lights, if the network card lights do not light, refer to dispatch Knowledge Base: "Network card lights are not bright or often not bright" solution
4, if the network card lamp Normal 1,2 step can not be resolved to lead the user to uninstall the network card driver, reload NIC driver, if the user XP system according to: Knowledge Number: 9973, how to set ADSL dial-up connection under WinXP to lead users to create a dial-up connection, If the 98 system recommends that users install Raspppoe software or EHERNET300 software connections.
5, if the above operation is invalid contact the Telecommunications department to confirm the port.

Code Encyclopedia
ADSL PPPoE dial-up Error section fault code introduction:
Error 602 The port is already open
Problem: dial-up Networking network cannot connect due to device installation error or is in use
Reason: PPPoE is not fully and correctly installed
Solution: Uninstall any PPPoE software, reinstall

Error 605 Cannot set port information
Problem: dial-up Networking Network cannot set use port due to device installation error
Reason: PPPoE is not fully and correctly installed
Solution: Uninstall any PPPoE software, reinstall

Error 606 The port is not connected
Problem: dial-up Networking network cannot connect required device ports
Reason: PPPoE is not fully and correctly installed, cable fault, ADSL modem fault
Solution: Uninstall any PPPoE software, reinstall, check cable and ADSL MODEM

Error 608 The device does not exist
Problem: Dial-Up Networking network connection device does not exist
Reason: PPPoE is not fully and correctly installed
Solution: Uninstall any PPPoE software, reinstall

Error 609 The device type does not exist
Problem: Dial-up network-connected devices whose types are not determined
Reason: PPPoE is not fully and correctly installed
Solution: Uninstall any PPPoE software, reinstall

Error 611 The route is isn't available/612 the route is not allocated
Problem: dial-up Networking network connection routing is incorrect
Reason: PPPoE is not fully and correctly installed, ISP server failure
Solution: Uninstall any PPPoE software, reinstall, call the ISP to inquire

Error 617 The port or device is already disconnecting
Problem: Dial-up network connected device is disconnected
Reason: PPPoE is not fully and correctly installed, ISP server failure, cable, ADSL modem fault
Solution: Uninstall any PPPoE software, reinstall, call ISP inquiries, check network cable and ADSL MODEM

Error 619
Problem: Unable to establish connection with ISP server
Reason: ADSL ISP server failure, ADSL telephone line fault
Solution: Check whether the ADSL signal lights can be synchronized correctly. Call your ISP to inquire

Error 621 cannot open the phone book file

Error 622 Cannot load the phone book file

Error 623 cannot find the phone book entry

Error 624 cannot write the phone book file

Error 625 Invalid Information found in the phone book
Problem: Windows NT or Windows Server Network RAS network component failure
Reason: Uninstall all PPPoE software, reinstall RAS network components and Raspppoe

Error 630
Question: ADSL Modem no response
Reason: ADSL telephone line fault, ADSL modem fault (power not open, etc.)
Solution: Check ADSL equipment

Error 633
Problem: dial-up Networking network cannot connect due to device installation error or is in use
Reason: PPPoE is not fully and correctly installed
Solution: Uninstall any PPPoE software, reinstall

Error 638
Problem: After a long time, unable to connect to the ISP's ADSL access server
Cause: ISP server failure; You have mistakenly entered a phone number in a bad connection created by PPPoE
Workaround: Run its create dial-up pppoe.exe check that the ISP service is listed to make sure that the ISP is working, clear the phone number from the dial-up connection you are using, or keep only one 0.

Error 645
Problem: NIC does not respond correctly
Cause: Nic failure, or NIC driver failure
Resolve: Check the network card, reinstall the NIC driver

Error 650
Problem: The remote computer is not responding, disconnect
Reason: ADSL ISP server failure, network card failure, abnormal shutdown caused by error
Solution: Check whether the ADSL lights can be correctly synchronized, call the ISP inquiries; Check the network card, remove all the networking components reinstall the network.

Error 651
Problem: The ADSL Modem report has an error
Reason: Windows is in Safe mode, or another error
Resolve: When this error occurs, redial, you can report a new specific error code

Error 691
Problem: Wrong username and password entered, unable to establish connection
Reason: Wrong username and password, ISP server failure
Workaround: Use the correct username and password and use the correct ISP account format (Name@service) to call the ISP for questioning.

Error 718
Problem: The remote computer timed out without responding when authenticating the user name, disconnecting
Reason: ADSL ISP server failure
Resolution: Call the ISP to inquire

Error 720
Issue: Dial-up Networking cannot coordinate protocol settings for servers in the network
Reason: ADSL ISP server failure, abnormal shutdown caused network protocol error
Resolve: Call the ISP to inquire, remove all network components and reinstall the network.

Error 734
Issue: PPP connection Control Protocol aborted
Reason: ADSL ISP server failure, abnormal shutdown caused network protocol error
Resolve: Call the ISP to inquire, remove all network components and reinstall the network.

Error 738
Problem: Server cannot assign IP address
Reason: ADSL ISP server failure, ADSL users too much more than the ISP can provide IP address
Resolution: Call the ISP to inquire

Error 769
Problem: NIC is disabled or NIC driver is not properly installed
Resolve: Check that the NIC driver is properly installed. If the NIC driver is normal, enter the Device Manager, the disabled Ethernet card status is set to enable, and then reconnect.

Error 797
Problem: ADSL modem connection device not found
Reason: ADSL modem power is not open, network card and ADSL modem connector problems, software installation after the corresponding agreement is not properly bound, in the establishment of dial-up connection, the establishment of the wrong empty connection
Resolve: Check the power supply, connectors, check Network properties, PPPoE related protocols are properly installed and properly bound (related protocols), check the network card appears? number or! number, set it to enable; Check the properties of the dial-up connection and whether the connected device uses an ISDN channel- Adapter Name (XX), the device is an empty device, if you use to cancel it, and choose the correct PPPoE device instead of it, or re-establish the dial-up connection.

Here are the possible error codes for using ADSL under Vista system:

798
A certificate could not be found that can be used for an Extensible Authentication protocol.

799
Internet Connection Sharing access (ICS) cannot be enabled because of an IP address conflict. ICS requires the host to be configured with 192.168.0.1. Make sure that no other clients on the network are configured to use 192.168.0.1.

800
Cannot establish a VPN connection. The VPN server may not be reachable, or the security parameters for this connection are not configured correctly.

801
This connection is configured to authenticate the access server, but Windows cannot verify the digital certificate sent by the server.

802
The provided card is not recognized. Please check that the card is plugged in correctly and is plugged in tightly.

803
The PEAP configuration saved in the session cookie does not match the current session configuration.

804
The PEAP identity saved in the session cookie does not match the current identity.

805
You cannot use this connection to dial when you log on because it is configured to use the Logged-on user ID.

90W
The connection between the computer and the VPN server has been started, but the VPN connection cannot be completed. The most common cause of this problem is that at least one Internet device (such as a firewall or router) between your computer and the VPN server is not configured to allow the generic Routing encapsulation (GRE) protocol pack. If the problem persists, contact your network administrator or Internet service provider.

807
The network connection between the computer and the VPN server was interrupted. This may be due to a problem that occurs during a VPN transfer, usually the Internet latency or only the result of a capacity limit that the VPN server has reached. Please try to reconnect to the VPN server. If the problem persists, contact the VPN Administrator and analyze the quality of your network connection.

808
The network connection between the computer and the VPN server could not be established because the remote server rejected the connection. This is usually caused by a mismatch between the server configuration and the connection settings. Contact the administrator of the remote server to verify your server configuration and connection settings.

809
The network connection between the computer and the VPN server could not be established because the remote server is not responding. This may be because a network device (such as a firewall, NAT, router, etc.) between the computer and the remote server is not configured to allow VPN connections. Www.111cn.net Contact your administrator or service provider to determine which device may be generating this problem.

810
The network connection between the computer and the VPN server was started, but the VPN connection was not completed. This is usually due to the use of incorrect or expired certificates for authentication between the client and the server. Contact your administrator to make sure that the certificate used for authentication is valid.

811
The network connection between the computer and the VPN server could not be established because the remote server is not responding. This is usually caused by a pre-shared key problem between the client and the server. Pre-shared keys are used to ensure that you are identified in the IP security settings (IPSEC) communication cycle. Ask your administrator for help to determine where the pre-shared key problem comes from.

812
The connection was blocked because of a policy configured on the RAS/VPN server. In particular, the authentication method that the server uses to authenticate user names and passwords may not match the authentication methods configured in the connection configuration file. Please contact the administrator of the RAS server and notify them of this error.

813
With the previous broadband connection in place, you are trying to establish another broadband connection using the same device or port. Disconnect the previous connection, and then re-establish the connection.

814
The basic Ethernet connection required for a broadband connection is not found. Before you try this connection, install and enable the Ethernet adapter on your computer over the Network Connections folder.

815
A broadband network connection cannot be established on the computer because the remote server is not responding. This may be caused by an invalid value for the Service Name field for this connection. Contact your Internet service provider to inquire about the correct value for this field and update it in the connection properties.

816
The remote Access Service no longer supports the features or settings that you are attempting to enable.

817
A connection cannot be deleted when it is connected.

818
Network Access Protection (NAP) enforcement clients cannot create system resources for remote access connections. Some network services or resources may not be available. If the problem persists, disconnect, retry the remote access connection, or contact the administrator of the remote access server.

819
The Network Access Protection Agent (napagent) service is disabled or not installed on this computer. Some network services or resources may not be available. If the problem persists, disconnect, retry the remote access connection, or contact the administrator of the remote access server.

820
The Network Access Protection (NAP) enforcement client was unable to register the network Access Protection Agent (napagent) service. Some network services or resources may not be available. If the problem persists, disconnect, retry the remote access connection, or contact the administrator of the remote access server.

821
The Network Access Protection (NAP) enforcement client was unable to process the request because the remote access connection does not exist. Please retry the remote access connection. If the problem persists, make sure you can connect to the Internet and then contact the administrator of the remote access server.

822
The Network Access Protection (NAP) enforcement client is not responding. Some network services or resources may not be available. If the problem persists, disconnect, retry the remote access connection, or contact the administrator of the remote access server.

823
The encrypted binding TLV received is invalid.

824
No encryption binding TLV received.

825
Point-to-Point Tunneling Protocol (PPTP) is incompatible with IPV6. Please change the type of virtual private network to the second tier Tunneling Protocol (L2TP)

826
EAPTLS validation of cached credentials failed. Please discard cached credentials.

827
The L2TP/IPSEC connection cannot be completed because the IKE and AuthIP IPSec key Module service and/or the basic Filter engine service are not running. The above services are required to establish a L2TP/IPSEC connection. Make sure these services are enabled before dialing connections.

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805
You cannot use this connection to dial when you log on because it is configured to use the Logged-on user ID.
90W
The connection between the computer and the VPN server has been started, but the VPN connection cannot be completed. The most common cause of this problem is that at least one Internet device (such as a firewall or router) between your computer and the VPN server is not configured to allow the generic Routing encapsulation (GRE) protocol pack. If the problem persists, contact your network administrator or Internet service provider.
807
The network connection between the computer and the VPN server was interrupted. This may be due to a problem that occurs during a VPN transfer, usually the Internet latency or only the result of a capacity limit that the VPN server has reached. Please try to reconnect to the VPN server. If the problem persists, contact the VPN Administrator and analyze the quality of your network connection.

808
The network connection between the computer and the VPN server could not be established because the remote server rejected the connection. This is usually caused by a mismatch between the server configuration and the connection settings. Contact the administrator of the remote server to verify your server configuration and connection settings.
809
The network connection between the computer and the VPN server could not be established because the remote server is not responding. This may be because a network device (such as a firewall, NAT, router, etc.) between the computer and the remote server is not configured to allow VPN connections. Contact your administrator or your service provider to determine which device may be generating this problem.
810
The network connection between the computer and the VPN server was started, but the VPN connection was not completed. This is usually due to the use of incorrect or expired certificates for authentication between the client and the server. Contact your administrator to make sure that the certificate used for authentication is valid.
811
The network connection between the computer and the VPN server could not be established because the remote server is not responding. This is usually caused by a pre-shared key problem between the client and the server. Pre-shared keys are used to ensure that you are identified in the IP security settings (IPSEC) communication cycle. Ask your administrator for help to determine where the pre-shared key problem comes from.
812
The connection was blocked because of a policy configured on the RAS/VPN server. In particular, the authentication method that the server uses to authenticate user names and passwords may not match the authentication methods configured in the connection configuration file. Please contact the administrator of the RAS server and notify them of this error.
813
With the previous broadband connection in place, you are trying to establish another broadband connection using the same device or port. Disconnect the previous connection, and then re-establish the connection.
814
The basic Ethernet connection required for a broadband connection is not found. Before you try this connection, install and enable the Ethernet adapter on your computer over the Network Connections folder.
815
A broadband network connection cannot be established on the computer because the remote server is not responding. This may be caused by an invalid value for the Service Name field for this connection. Contact your Internet service provider to inquire about the correct value for this field and update it in the connection properties.
816
The remote Access Service no longer supports the features or settings that you are attempting to enable.
817
A connection cannot be deleted when it is connected.
818
Network Access Protection (NAP) enforcement clients cannot create system resources for remote access connections. Some network services or resources may not be available. If the problem persists, disconnect, retry the remote access connection, or contact the administrator of the remote access server.
819
The Network Access Protection Agent (napagent) service is disabled or not installed on this computer. Some network services or resources may not be available. If the problem persists, disconnect, retry the remote access connection, or contact the administrator of the remote access server.
820
The Network Access Protection (NAP) enforcement client was unable to register the network Access Protection Agent (napagent) service. Some network services or resources may not be available. If the problem persists, disconnect, retry the remote access connection, or contact the administrator of the remote access server.
821
The Network Access Protection (NAP) enforcement client was unable to process the request because the remote access connection does not exist. Please retry the remote access connection. If the problem persists, make sure you can connect to the Internet and then contact the administrator of the remote access server.
822
The Network Access Protection (NAP) enforcement client is not responding. Some network services or resources may not be available. If the problem persists, disconnect, retry the remote access connection, or contact the administrator of the remote access server.
823
The encrypted binding TLV received is invalid.
824
No encryption binding TLV received.
825
Point-to-Point Tunneling Protocol (PPTP) is incompatible with IPV6. Please change the type of virtual private network to the second tier Tunneling Protocol (L2TP)
826
EAPTLS validation of cached credentials failed. Please discard cached credentials.
827
The L2TP/IPSEC connection cannot be completed because the IKE and AuthIP IPSec key Module service and/or the basic Filter engine service are not running. The above services are required to establish a L2TP/IPSEC connection. Make sure these services are enabled before dialing connections.