Make your own free website on






ERROR 645 For Windows 98

Error 645 Discussion Board  If the fixes below didn't work... Post your problem / solution here!! 

Error 645 from Microsoft Dial Up Networking "Internal Authentication Error"

 Google News Information Error 645

 Microsoft Support Page Error 645 

When you attempt to establish a connection with Dial-Up Networking (DUN), you may receive the  following error message:
Error 645 - Dial-Up Networking could not complete the connection to the server. 

Solution #1
This behavior can occur if the Require encrypted password option is enabled on the Server Types tab in
  the connection's properties.
  To resolve this behavior:
  1. Click Start, point to Programs, point to Accessories, point to
     Communications, and then click Dial-Up Networking.
  2. Right-click the icon for your connection, and then click Properties.
  3. Click the Server Types tab, click to clear the Require encrypted password
     check box, and then click OK.
  4. Enable Software Compression and TCP/IP should be the only two property boxes check marked.

Solution #2
What's A Modem Init String?
Try adding modem init string ATZ. This seems to work with many laptop computers.
How To Add a Modem Init String

Solution #3 (Laptop Computers w/PCMCIA cards)
Try moving modem card to another PCMCIA card socket.

Solution #4
  Remove and reinstall the Dial-Up Adapter and Dial-Up Networking. To do so, use the following steps:
 1. Click Start, point to Settings, and then click Control Panel.
  2. Double-click Network.
  3. Click Dial-Up Adapter, and then click Remove.

  4. Click OK.
  5. When you are prompted to restart your computer, click No.
  6. Double-click Add/Remove Programs.
  7. On the Windows Setup tab, click Communications, and then click Details.
  8. Click the Dial-Up Networking check box to clear it.
  9. Click OK until you return to Windows.
  10. Close Control Panel, and then restart the computer.
 11. Go to My Computer, Dial Up Networking, and try to reconnect.

Solution #5
bulletCreate a connectoid in Dial Up Networking
bulletMake sure that  Log onto Networks, IPX/SPX, NetBeui is uncheck marked in Server Types.
bulletCheck winsock.dll and wsock32.dll location and sizes
bulletDelete all existing connectoids in DUN, as well as shortcut to desktop.
bulletGo into Control Panel, Network and remove all components.
bullet In Control Panel, Add/Remove programs, windows setup tab uncheck connection. click OK...
bulletIn Control Panel, Add/Remove programs, recheck connection, click ok.
bulletReboot if prompted.
bulletGo into control panel, Network, Add Client for Microsoft Network, Dial up Adapter, Tcp/IP.
bulletClick Tcp/Ip than properties. Make sure that Wins Resolution and DNS is disabled. Click OK...
bulletReboot computer when prompted.
bulletIf Windows 95, Try uninstalling Microsoft Dial Up Networking? In add/remove
bulletRetype password
Reinstall DUN
Log off ...? Existing profile, log on?