I'm getting the below error across multiple servers (SQL Server 2005, 2008, 2008r2, 2012). The SQL Servers are up to date with service packs as is the OS. These are all SQL Server Standard edition.

The server's OS was patched this weekend and all the servers were rebooted. So I'm assuming this what they have in common.

Researching this has led me in too many directions and due to the large number of servers impacted (19), nothing is really making sense to me.

Any suggestions what is causing this? And how do I deal with it?

The relevant error message:

The prelogin packet used to open the connection is structurally invalid; the connection has been closed. Please contact the vendor of the client library. [CLIENT:]
- <Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
- <System>
  <Provider Name="MSSQL$myserver" /> 
  <EventID Qualifiers="49152">17828</EventID> 
  <TimeCreated SystemTime="2018-10-29T06:14:58.000000000Z" /> 
  <Security /> 
- <EventData>
  • 3
    We get this when security scanning software hits our servers. See if is a security scanning server. Oct 29, 2018 at 18:59
  • The source IP, is it another server or a client's desktop/laptop? Either way I would look at that first... check it for malware, compromised software, etc etc... reboot it.. clean it and reboot again... and then try and connect to your database from it manually using all the accounts you know... it's a cryptic msg that sends you into Wonderland.
    – Fandango68
    Apr 6 at 20:25


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.