Dedicated Admin Console (DAC) a reserved connection on SQL Server that grants special access to system tables and can help diagnose problems
Questions tagged [dac]
24 questions
16
votes
3 answers
Is it possible to estabilish Dedicated Administrator Connection (DAC) using SSMS?
Is it possible to connect to the DAC using SSMS?
If I understand correctly, it should be possible by using "admin:" prefix before the server name, but I receive the following message:
Dedicated administrator connections are not supported via SSMS…
user6426
7
votes
2 answers
Enabling admin connection on SQL Server Express to fix logon trigger
Well, luckily I got this error on my test environment. I'm so scared about this error that I disabled all logon triggers I was using on production environment.
I created the famous logon trigger, and I put a database in offline mode just to mess…
Racer SQL
- 7,546
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5
votes
2 answers
"the maximum number of '1' dedicated administrator connections already exists" message in error log when connecting to DAC from Powershell
I'm connecting to SQL Server (2016 and 2017 latest builds) via the Dedicated Administrator Connection (DAC) from PowerShell.
The following error message is recorded in the SQL Server Error Log:
Date 4/2/2019 1:59:13 PM
Log SQL Server…
RelativitySQL
- 217
- 2
- 7
5
votes
1 answer
Static DAC ports for named instances
Using SQL 2016 Enterprise Edition
The default instance will listen on 1433 and the DAC port will listen on TCP 1434. SQL Browser will listen on UDP 1434. Any subsequent named instances will get a dynamically allocated port from windows in the range…
Gavin Harris
- 135
- 1
- 7
4
votes
1 answer
How do I log into the Dedicated Admin Console (DAC) on Linux?
sqlcmd is documented to have,
Login-Related Options
-A
Logs in to SQL Server with a Dedicated Administrator Connection (DAC). This kind of connection is used to troubleshoot a server. This will only work with server computers that support DAC. If…
Evan Carroll
- 65,432
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4
votes
1 answer
Is it possible to connect MS SQL Server Express 2012 through DAC Connection?
Is it possible to Connect MS SQL Server 2012 Express Through DAC. After moving from SQL Server 2012 Enterprise to MS SQL Server 2012 Express, some performance problem were there. When i have checked out using this TSQL
select * from…
Md Haidar Ali Khan
- 6,523
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3
votes
2 answers
Why SQL Server Service Account connects to the DAC?
We started getting Alerts:
Could not connect because the maximum number of '1' dedicated administrator connections already exists. Before a new connection can be made, the existing dedicated administrator connection must be dropped, either by…
VitalicJJ
- 55
- 1
- 8
3
votes
1 answer
How do we find who used Dedicated Admin Connection
Is there any way to find who used Dedicated Admin Connection?
Not active connection but the previous one which is already closed?
Santhoshkumar KB
- 581
- 2
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3
votes
1 answer
How do I know what requires DAC?
Playing around with SQL Server, I came across a semi-cryptic error. Essentially, I only need to log into DAC. Is there any general advice for when DAC is needed? How do I know I need it to access sys.sysobjvalues without googling for the error…
Evan Carroll
- 65,432
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2
votes
2 answers
DAC connection error
I'm having a problem connecting using my dedicated admin connection in SQL Server 2014. I just wanted to test it out.
I have DAC enabled in sp_configure. I have performed RECONFIGURE.
I have prefixed my connection string with ADMIN: in SSMS Connect…
user3469285
- 671
- 2
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- 19
2
votes
0 answers
Severity 20 Error upon disconnecting Dedicated Administrator Connection
Starting working with Dedicated Administrator Connections on SQL Server 2008 R2 servers. All is working fine (once port 1434 was opened), but am getting severity 20 errors when I disconnect the admin connection.
From within SSMS, I am opening a new…
CJ Gregory
- 21
- 2
2
votes
1 answer
Are harmless sp_configure commands always safe to run?
Suppose that I wish to run the following
/* Check for any pending configurations, just in case. */
SELECT *
FROM sys.configurations
WHERE value <> value_in_use;
GO
EXEC sp_configure 'remote admin connections', 1;
GO
RECONFIGURE
GO
Is there any…
J. Mini
- 1,161
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2
votes
1 answer
Azure SQL Database - dedicated administrator connection (DAC)
If you check the setting in any of your Azure SQL databases, you will see that the value_in_use column value is zero for Remote admin connections. Meaning ‘Remote admin connections’ are not allowed from remote clients. There is no way to change that…
SqlWorldWide
- 13,687
- 3
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2
votes
0 answers
DAC silently swallows tokenization errors in sp_msforeachdb
This morning I hopped on the DAC to check something out. Oops, I made a typo!
1> exec sp_msforeachdb N'
2~ use [?]
3~ select N'?', count(*) from sys.sysrscols;
4~ '
5> go
1>
Can you spot my error? Pretty obvious when you see it, right? It's even…
Peter Vandivier
- 5,485
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2
votes
1 answer
Why am I getting "Invalid object name 'sys.sysobjvalues'."
When I run
SELECT OBJECT_DEFINITION(OBJECT_ID('sys.assembly_files'));
I can see that there is a self-join on sys.sysobjvalues, but when I try to select that table I get,
Msg 208, Level 16, State 1, Line 1
Invalid object name…
Evan Carroll
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