DUN Error 629: The port was disconnected by the remote machine.

SYMPTOMS

When you attempt to connect to a remote computer by using Dial-Up Networking, you may receive one of the following error messages:

• Error 629: The port was disconnected by the remote machine.

CAUSE

This is a generic timeout error message during the dial-up connection phase of DUN with either an analog modem or ISDN TA (terminal adapter). This issue can occur if one of the following scenarios is true:

• The customer has entered the wrong username and/or password into the DUN connectoid he/she is using (authentication error) if he/she is connecting into a PAP PoP (Point of Presence).
• The modem is trying to connect at a speed that modem handshake is unable to negotiate over the phone line due too much noise/interference on the phone line the customer is using.
• DUN and/or TCP/IP could have corrupt or improper (mixed) version of their files and/or corruption with their registry entries.

Be aware that some DSL customers also using WinPoET or RASPPPoE can also be subject to this error message. (WinPoET and RASPPPoE are VPN-like PPPoE (Point-to-Point Protocol over Ethernet) clients to allow DSL customers to authenticate onto Redback servers so that they can initialize their DSL Internet connections. This issue can occur if one of the following scenarios is true:

• The ISP's Redback servers are not responding to authentication requests.
• The customer's DSL modem is not getting sync with his/her local telco's DSLAM.
• The customer's network connectivity (either hardware, software, or both) is not functioning between his/her NIC and the DSL modem.

For the most part, the resolutions below in the next section deal with teching a dial-up Internet access account, not a DSL account. However, the third solution listed below can help solve the above if the problem is not with the ISP's redback nor a problem with the DSL modem not getting sync (with the exception of instructions on how to reinstall the PPPoE adapters protocols in the Network control panel).

RESOLUTION

From what is listed in the above section, there is a wide variety of possible causes of this error (user error, hardware difficulty, and corrupt software). To solve this particular problem, fix the easiest and most likely causes of this error message in order from most likely to least likely. The order listed above for the possible causes are in that particular order.

Check if the customer is failing DUN authentication

The most likely possibility is that the customer is failing authentication and also usually the easiest to check if you have access to the ISP's RADIUS logs. Unfortunately, if you're not the ISP providing support to the customer, you won't have access to grep those RADIUS logs. It is usually best to tell the customer to contact the ISP to see if they can tell if the customer is failing authentication because the following two sections can and possibly will be a waste of time, even if you have access to the customer's username and password, because the PoP that the customer is using might be experiencing authentication problems. However, if one wants to help the customer check to see if there's a possible problem with her username and/or password (whether it be user error, data corruption, or a PoP failing authentication), follow the steps below to test authentication via HyperTerminal.

Follow these instructions to open HyperTerminal in Win95:

1. Click on Start | Programs | Accessories | HyperTerminal.
2. Open the HYPERTRM.EXE file from within the folder that was just opened.
3. For the name of the connection, type the number 1 and then hit Enter key.
4. For the phone number, type the number 1 and then hit the Enter key
5. Hit the Esc key to exit that last window.

Follow these instructions to open HyperTerminal in Win98/Me:

1. Click on Start | Programs | Accessories | Communications | HyperTerminal.
2. Open the HYPERTRM.EXE file from within the folder that was just opened.
3. For the name of the connection, type the number 1 and then hit Enter key.
4. For the phone number, type the number 1 and then hit the Enter key
5. Hit the Esc key to exit that last window.

Follow these instructions to open HyperTerminal in WinNT:

1. Click on Start | Programs | Accessories | Communications | HyperTerminal.
2. For the name of the connection, type the number 1 and then hit Enter key.
3. For the phone number, type the number 1 and then hit the Enter key.
4. Hit the Esc key to exit that last window.

Once you've opened HyperTerminal, enter the following commands into the terminal window. At the end of each command line, hit the Enter key. Do not type the comments/remarks that are listed in parentheses to the right of the commands.

1. ATE1          (turns the echo mode for the modem on so that it will echo back what is typed into the terminal window)
2. ATDTnumber          (the "number" needs to be exact phone number that the customer needs to dial in order for him/her to connect to his/her ISP's PoP)
3. username          (the "username" is the customer's username with his/her ISP)
4. password          (the "password" is the customer's password with his/her ISP)

After the customer's modem is done handshaking with the ISP's modem, there will be 1 of 3 possible responses that will show in the terminal window.

• It will show the words NO CARRIER which indicates that there is modem negotiation problems.
• It will show a bunch of random special ASCII characters when it should be receiving plain text characters streaming across the window. This indicates that there is too much line noise for the speed the modems had negotiated.
• It will show a username prompt (possibly also showing the name of the modem rack and/or a welcome message from the ISP) for the customer to type in his/her username and then hit the Enter key. After the customer typed in the username, a password prompt will show for him to type his/her password and then hit the Enter key. After this, the terminal window will show that PPP packet mode has been enabled if the customer typed the correct username or password, or will show an error message telling the customer there was a problem with either the username or the password he/she typed.

If the customer is still having problems with authentication failure in the above third scenario, then have the customer call his/her ISP. For those customers affected by the first two scenarios, they will need to follow the troubleshooting steps in the next resolution section to slow the modem down. If the customer is able to connect via HyperTerminal successfully, have him/her try to connect via DUN again. If the customer still receives the same error message, then have him/her move onto the third resolution section to fix DUN and/or TCP/IP

Slow the customer's modem down

If one can verify that the customer isn't even getting to the authentication stage in the DUN connection via HyperTerminal, then the next easy step is to slow the customer's modem down. Most customers these days will have 56K Winmodems in their computers, in which case one should force the modem to connect at the V.34 protocol (28800 bps) or V.34+ protocol (33600 bps) by disabling the 56K protocols that are on the customer's particular modem (whether they will be x2, K56Flex, and/or V.90). If you're still having problems getting the customer to the authentication stage in the connection, then one must force the modem to connect at the V.32bis procotol (14400 bps) to hopefully be able to connect through whatever line noise is on the customer's phone line.

Completely uninstall/reinstall DUN and TCP/IP networking components

If one can verify that the customer is entering the correct authentication information and that the modem is getting to the authentication stage, there is most likely a possible problem with the networking components of DUN and/or TCP/IP. A complete uninstall/reinstall of those networking components should solve the problem at that point.

Before one begins to uninstall/reinstall any networking component, one must check the customer's computer for which version of Windows he/she has installed and make sure that the customer has the original installation files (the win*.cab files for Win9x installations) either on the HD, a CD-ROM, or floppies. The instructions listed below show one how to do both.

1. Right-click on the My Computer icon on the desktop.
2. Click on the Properties option on the pop-up menu.
3. Have the customer read off the Windows version number in the first paragraph.
4. Enter that Windows version number into the call log.
5. Click on the Cancel button.
6. Click on Start | Find | Files or Folders... (for Win95 or Win98) or Start | Search | For Files or Folders... (for WinMe).
7. In the "Named:" box, type win*.cab
8. Make sure that the (C:) drive is selected in the "Look In:" box
9. Hit the Enter key to begin the search.
10. Have the customer read the date that is listed for all of the .cab files that appear under the Modified column in the search results window pane.
11. Type the date the customer reads off into the call log.
12. Compare the Windows version installed with the .cab files available to see if they are matching versions.

Once it has been determined that the customer's version of Windows matches the original installation files that are immediately accessable (on HD, CD-ROM in the CD-ROM drive, or the first floppy disk in the floppy drive), one can begin to remove and reinstall the DUN and TCP/IP files and registry settings on the computer. If one finds that the customer doesn't have a matching version between what's installed and the original media that the customer has on hand, then you'll need to end the call with the customer as soon as possible instructing him/her to obtain the original installation media for his/her current installation of Windows. One cannot help the customer any further once it has been determined that the customer does not have matching versions of Windows installed and on the original installation media

Do the following to uninstall DUN and TCP/IP on Win9x:

NOTE: Before you about removing registry entries, you will want to make sure you are familiar with using the Registry Editor. If you are not familiar with doing the above, please check with another technician or manager for details.

1. Click on Start | Settings | Control Panel
2. Double-click on the Network icon.
3. Remove all instances of TCP/IP and any unnecessary adapters and other protocols that the customer is not using and/or has no longer installed.
4. Click on the OK button.
5. Click on the Yes button on any "version conflict" windows that may pop up when Windows is copying files.
6. Click on the No button when Windows asks you to restart the computer.
7. Double-click on the Add/Remove Programs icon.
8. Click on the Windows Setup tab at the top of that window.
9. Uncheck the Communications components group.
10. Click on the OK button.
11. Click on the Yes button on any "version conflict" windows that may pop up when Windows is copying files.
12. Click on the No button when Windows asks you to restart the computer.
13. Close all windows that are currently open.
14. Click on Start | Shut Down... | Restart | Yes or OK.
15. Wait for the Windows desktop to reappear on the screen.
16. Click on Start | Run...
17. Type regedit and then hit the Enter key.
18. Remove the following registry keys:
• HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Winsock
• HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Winsock2
• HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\RemoteAccess\Authentication\SMM_Files
• HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\VxD\AFVXD
• HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\VxD\DHCP
• HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\VxD\MSTCP
• HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\VxD\Winsock
• HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\VxD\Winsock2
19. Close out of the Registry Editor.

There could still possibly be a problem with the customers installation of Windows, his/her modem, his/her phone line, and/or his/her ISP. One could do the absolutely complete removal and reinstall of DUN and TCP/IP from the Microsoft Knowledge Base articles listed below; however, this would be best left to Microsoft and/or the original computer manufacturer to follow those extremely detailed instructions.

MORE INFORMATION

For the absolutely complete instructions for removing and reinstalling DUN and TCP/IP, check out these Microsoft KB articles:

• How to Remove and Reinstall Dial-Up Networking and TCP/IP Files (Q181599)
• How to Extract Original Compressed Windows Files (Q129605)

©2002 Christopher Morton