Monday, 30 January 2017

Enabling Remote Access to the Dedicated Admin Connection

Recently I was running a health check on one of my clients SQL Servers and I noticed that access to the dedicated admin account was disabled. They would not be able to connect to the Dedicated Admin Account (DAC) remotely.  It is generally good practice to enable remote admin connections. If you have a server that is under so much load that all the resources are used up. SQL Server always allows saves enough resources for one single session to connect. You can’t use object explorer so you will be limited to one Query Window or connect through SQLCMD.  Enabling this would allow my clients in-house DBAs to connect to the DAC when you are not physically connected to the SQL Server in question should the need arise.

This is a pretty useful feature and whilst you can use a local DAC connection by default. That is, when you are connected locally to the server in question, you can connect using the DAC. If you want to connect remotely you need enable the ‘remote admin connections’ server options.

You can check is the ‘remote admin connections’ is enabled by running the following query

SELECT *
FROM sys.configurations

-->
where name like 'remote admin connections'

A value_in_use of 0 indicates local connections. A value of 1 means that remote connections are enabled


You can change the option if you need by using SP_CONFIGURE and the code below

Use master
GO
sp_configure 'remote admin connections', 1
GO
RECONFIGURE

-->
GO

Enabling the DAC can be a lifesaver if you get a rogue query chewing up all the resources on a server and it can be a good idea to enable it. I wrote a post over 6 years ago saying to connect to the DAC you can see the link to that below

Related Posts
Connecting using the DAC - http://www.gethynellis.com/2010/09/sql-server-dedicated-administrator.html



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