Want to win a PS4? Go Premium and enter to win our High-Tech Treats giveaway. Enter to Win

x
?
Solved

SChannel errors on the two DCs in the domain

Posted on 2016-09-03
7
Medium Priority
?
2,377 Views
Last Modified: 2016-09-10
There are continual event id 36888 in each DC's log as follows:  ""A fatal alert was generated and sent to the remote endpoint. This may result in termination of the connection. The TLS protocol defined fatal error code is 10. The Windows SChannel error state is 1203."

In addition, dcdiag displays (In part)

     Starting test: SystemLog
         An error event occurred.  EventID: 0x00009018
            Time Generated: 09/03/2016   09:01:15
            Event String:
            A fatal alert was generated and sent to the remote endpoint. This ma
y result in termination of the connection. The TLS protocol defined fatal error
code is 10. The Windows SChannel error state is 1203.
         An error event occurred.  EventID: 0x00009018
            Time Generated: 09/03/2016   09:01:15
            Event String:
            A fatal alert was generated and sent to the remote endpoint. This ma
y result in termination of the connection. The TLS protocol defined fatal error
code is 10. The Windows SChannel error state is 1203.
         ......................... WWE-DC failed test SystemLog


Both DCs get them, but one side gets way more.  Each is 2012 R2 and has Essentials role installed.  VPN is full time between two sites at close to 100MBS.

My questions are a) what is the cause of this,  i.e., where can I find additional information to pinpoint the cause, and b) what do I do with it to fix the issue>
0
Comment
Question by:lmheimendinger
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 3
  • 3
7 Comments
 
LVL 18

Expert Comment

by:Learnctx
ID: 41783311
The cause is most likely an encrypted connection attempt when the DC's are not configured to accept LDAPS (LDAP over SSL) connections or the client is trying to use a cipher the DC does not accept. Do you offer LDAPS? If you do your DC's will be listening on the following ports for LDAP.

389 (LDAP)
636 (LDAPS)
3268 (LDAP GC)
3269 (LDAPS GC)

There is a list of Schannel error codes here. In your case you're receiving error 10, which would be SSLv3. Some applications will try an LDAPS bind first and then fall back to LDAP which can generate these errors if you're not offering up LDAPS. If you do not offer LDAPS you can ignore these errors.
0
 
LVL 38

Expert Comment

by:Mahesh
ID: 41783376
DCdiag will show error logs during systemlog test

by default domain controllers do listen on TCP 636 as well in addition to 389

I believe you are not using any secure LDAP bind or connection, for that you do need SSL cert on DC and also AD service need to be configured for that

If you are running any browser based application from DC, untick all TLS options from IE options\advanced page

If that's not the case, navigate to HKLM\SYSTEM\CurrentControlSet\Control\SecurityProviders\Schannel
 Value Name: EventLogging
  change this value from 1 to 0 - this value causes most of the errors are generating
0
 

Author Comment

by:lmheimendinger
ID: 41783820
Learnctx WIndows Firewall has all of those ports open...

Mahesh - There was no key on either server for SChannel under SecurityProviders.. should I create one?  Is EventLogging binary or a double word 32-bit?
0
Looking for the Wi-Fi vendor that's right for you?

We know how difficult it can be to evaluate Wi-Fi vendors, so we created this helpful Wi-Fi Buyer's Guide to help you find the Wi-Fi vendor that's right for your business! Download the guide and get started on our checklist today!

 
LVL 38

Expert Comment

by:Mahesh
ID: 41783886
You can create key as per screenshot attachedSChannel - reg dword-32

But this will just suppress errors, if you are not running any certificate based operation on DC, you can ignore it.

To find out root cause you need to capture inbound traffic to DC to identify source of encrypted traffic
0
 

Author Comment

by:lmheimendinger
ID: 41783944
I am not seeing any apps that do this, assumed it was DC->DC error....
0
 
LVL 38

Accepted Solution

by:
Mahesh earned 2000 total points
ID: 41783972
DC to DC communication will not happen over 636 (LDAPS) unless you configured explicitly
0
 

Author Closing Comment

by:lmheimendinger
ID: 41793109
ended up ignoring
0

Featured Post

Veeam Task Manager for Hyper-V

Task Manager for Hyper-V provides critical information that allows you to monitor Hyper-V performance by displaying real-time views of CPU and memory at the individual VM-level, so you can quickly identify which VMs are using host resources.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

After seeing many questions for JRNL_WRAP_ERROR for replication failure, I thought it would be useful to write this article.
Microsoft Office 365 is a subscriptions based service which includes services like Exchange Online and Skype for business Online. These services integrate with Microsoft's online version of Active Directory called Azure Active Directory.
In this Micro Tutorial viewers will learn how they can get their files copied out from their unbootable system without need to use recovery services. As an example non-bootable Windows 2012R2 installation is used which has boot problems.
In this Micro Tutorial viewers will learn how to restore single file or folder from Bare Metal backup image of their system. Tutorial shows how to restore files and folders from system backup. Often it is not needed to restore entire system when onl…

609 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question