16
votes
Accepted
How do we find who used Dedicated Admin Connection
SQL Server doesn't maintain this information anywhere; if you're trying to catch someone abusing the DAC, either take away sysadmin from the people who clearly shouldn't have it, or at least set up ...
- 182k
10
votes
Accepted
Static DAC ports for named instances
Taken from the Microsoft Support site:
To configure a static port for the specialized Dedicated Administrator Connection (DAC), you must update the registry key that corresponds to your instance. For ...
- 70.5k
7
votes
Accepted
Enabling admin connection on SQL Server Express to fix logon trigger
The documentation for "Diagnostic Connection for Database Administrators" states:
To conserve resources, SQL Server Express does not listen on the DAC port unless started with a trace flag 7806.
...
- 69.5k
5
votes
Accepted
Why do I need DAC if I am able to connect to the server via sqlcmd?
Referencing Diagnostic Connection for Database Administrators with highlighting mine:
SQL Server provides a special diagnostic connection for administrators
when standard connections to the ...
5
votes
Accepted
No DAC connection could be established on the default port. Make sure DAC is enabled
From Using a Dedicated Administrator Connection:
By default, the connection is only allowed from a client running on the server. Network connections are not permitted unless they are configured by ...
- 182k
4
votes
Accepted
How do I log into the Dedicated Admin Console (DAC) on Linux?
Clients
There are two Linux clients from Microsoft that can connect to SQL Server's Dedicated Administrator Connection (DAC),
mssql-cli. Versions newer than 0.90 have the -A option to connect to the ...
- 64.7k
3
votes
No DAC connection could be established on the default port. Make sure DAC is enabled
Enabling the remote admin connection allows you to access the DAC from another machine on your network, otherwise you would only be able to access it from the local machine where SQL Server is running ...
- 4,043
3
votes
No DAC connection could be established on the default port. Make sure DAC is enabled
The Remote DAC is very useful in an emergency situation where the server is so pinned down that you can't even RDP to it. If you aren't able to use sqlcmd, SSMS or any other query tool except on the ...
- 5,986
2
votes
Azure SQL Database - dedicated administrator connection (DAC)
As per Microsoft documentation, Diagnostic Connection for Database Administrators is available for the Azure SQL database. If you are not familiar with DAC, read this official documentation from ...
- 13.6k
2
votes
Is it possible to estabilish Dedicated Administrator Connection (DAC) using SSMS?
I spent a couple of days trying connect to the DAC with SSMS to my SQL sandbox server. I read this post, everything tagged 'dac. I even found some posts missing the tag and added it.
My frustration ...
- 6,318
2
votes
Why am I getting "Invalid object name 'sys.sysobjvalues'."
This is one of the tables that can only be accessed over DAC, from this blog
They had been moved to the imageval column of sys.sysobjvalues, which can only be accessed when using the Dedicated ...
- 64.7k
2
votes
Accepted
SQL Server Error "Database 'mssqlsystemresource' does not exist."
The mssqlsystemresource database is only available in single-user mode. On Linux, that means
sudo systemctl stop mssql-server
sudo -u mssql /opt/mssql/bin/sqlservr -m
- 64.7k
2
votes
SQL Server Management Studio DAC connection error
TcpDynamicPorts in regedit was set to 59036
Your instance is named and is configured to use dynamic ports.
The default instance is listening on 1433 for all the connections and on 1434 for DAC, your ...
- 11.2k
2
votes
Enabling admin connection on SQL Server Express to fix logon trigger
Use Reset-DbaAdmin to gain your access back.
This function allows administrators to regain access to local or remote SQL Servers by either resetting the sa password, adding sysadmin role to ...
- 62.4k
2
votes
"the maximum number of '1' dedicated administrator connections already exists" message in error log when connecting to DAC from Powershell
After working up through several layers of Microsoft support, it was discovered that the solution to this issue was to change pooling=false to Pooling=False - apparently keywords and values are case ...
- 217
1
vote
Why SQL Server Service Account connects to the DAC?
As Kin mentioned in his answer, this appears to be some kind of virus scanner or port scanner that's running locally on the SQL Server box. Especially given these clues:
Comes from two different ...
- 29.8k
1
vote
Why SQL Server Service Account connects to the DAC?
I recon that this is port/virus scanner that your security team might be using to find out vulnerabilities e.g. weak passwords. I had the same issue and eventually I figured out that it was the port ...
- 62.4k
1
vote
SQL Server Management Studio DAC connection error
Since you have already on local machine of SQL Server, there is no need of configuring exec sp_configure 'remote admin connections', 1. It's good practice in security terms to have DAC available only ...
- 2,437
Only top scored, non community-wiki answers of a minimum length are eligible