We are using Microsoft SQL Server 2017 with Windows Failover Cluster on 2012 server.
We are getting 1000's of login errors in SQL error log coming from the Microsoft Failover Cluster Virtual Adapter and preceding this error is perhaps an IPV6 connection. We get multiples of these errors. First it starts coming from source [CLIENT: ::1], then we get the adapter error following that over and over again. The cluster log shows no issues.
This address [CLIENT: x.x.x.x] is the actual Microsoft Failover Cluster Virtual Adapter shown below. I have de-identified it.
We have IPV6 turned off but what I read is that Clustering still uses IPV6 over IPV4. Anyhow I would like to know what account is trying to connect to SQL and why it is erroring. Pretty much the connection never gets put through. What account is being used do you think? Is this part of the hearbeat check? Error below. Thanks.
Logon,Unknown,Error: 17830<c/> Severity: 20<c/> State: 11.
Logon,Unknown,Network error code 0x2746 occurred while establishing a connection; the connection has been closed. This may have been caused by client or server login timeout expiration. Time spent during login: total 0 ms<c/> enqueued 0 ms<c/> network writes 0 ms<c/> network reads 0 ms<c/> establishing SSL 0 ms<c/> network reads during SSL 0 ms<c/> network writes during SSL 0 ms<c/> secure calls during SSL 0 ms<c/> enqueued during SSL 0 ms<c/> negotiating SSPI 0 ms<c/> network reads during SSPI 0 ms<c/> network writes during SSPI 0 ms<c/> secure calls during SSPI 0 ms<c/> enqueued during SSPI 0 ms<c/> validating login 0 ms<c/> including user-defined login processing 0 ms. [CLIENT: x.x.x.x]