Reason 401: An unrecognized error occurred while establishing the VPN connection

Posted on 2007-07-21
Medium Priority
Last Modified: 2011-05-05
I tried to connecting vpn but...


Initializing the connection using certificate "egarcomputers"
Initiating TCP to xxx.xxx.xx.xx...
Contacting the security gateway at xxx.xxx.xx.xx...
Secure VPN Connection terminated locally by the Client.
Reason 401: An unrecognized error occurred while establishing the VPN connection.

Connection terminated on: srp 19, 2007 16:58:08        Duration:
Not connected.


Cisco Systems VPN Client Version
Copyright (C) 1998-2005 Cisco Systems, Inc. All Rights Reserved.
Client Type(s): Windows, WinNT
Running on: 5.1.2600 Service Pack 2
Config file directory: C:\Program Files\Cisco Systems\VPN Client\

1      16:58:07.703  07/19/07  Sev=Warning/2      CERT/0xE3600001
Failed to sign hash: B_EncryptInit() failed

2      16:58:07.703  07/19/07  Sev=Warning/2      IKE/0xE3000099
Failed to generate signature: Signature generation failed (SigUtil:97)

3      16:58:07.703  07/19/07  Sev=Warning/2      IKE/0xE3000099
Failed to build Signature payload (MsgHandlerMM:489)

4      16:58:07.703  07/19/07  Sev=Warning/2      IKE/0xE3000099
Failed to build MM msg5 (NavigatorMM:312)

5      16:58:07.703  07/19/07  Sev=Warning/2      IKE/0xE30000A5
Unexpected SW error occurred while processing Identity Protection (Main Mode) negotiator:(Navigator:2202)

thank you for solution.
Question by:egarcomputers
  • 3
  • 2

Expert Comment

ID: 19544972
are you connecting to a vpn from your home? do you have a router at home you are connecting through? Sometimes you need to enable ipsec passthrough for this to work


Author Comment

ID: 19545554
I'm connecting from home trought internet ADSL without router. Enable ipsec passthrough is
used only for ROUTER?

Expert Comment

ID: 19546302
no, what is your OS. Windows has a firewall also and may be disabling the ports needed to operate. I think you need UDP port 500 open, and maybe another. I will have to double check what ports the CIsco VPN uses, but I have to leave. I will check back later.

If you do have Windows XP with SP2 your firewall settings are in the control panel. You can open it from there and configure. Since you are directly connected to the net, I would suggest keeping this enable. Normally I would say just disable and test, but with no other security I would worry about that.

You could also have a software firewall running like Norton Internet Security or McAffee.

Good luck


Author Comment

ID: 19551510
I have windows xp sp2. I turn off windows firewall and also PC-cillin antivirus but the same error
will appear. One month ago I can't have any problem with vpn connection.
Then I have some mistake on hard disk and I must format it and reinstall OS.
After reinstallation  OS I can't connecting vpn.
Thank you for any suggestion.

Accepted Solution

mdefalco earned 1500 total points
ID: 19552556
So how is the Cisco VPN client configured? If you worked before, then your ISP is allowing this traffic, and you do not have any firewalls, so it has to be the software.

Were you given a file to import into the VPN client for remote access, or are you manually configuring the client?

It seems to me your problem lies in the configuration of the Cisco VPN software. Do you know someone else who is connected properly using the same software? If so try and copy their settings.


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