SQL Linked Server Login failed for user 'NT AUTHORITY\ANONYMOUS LOGON'

Sometimes when trying to access a linked server, you’d get an error saying “Login failed for user NT AUTHORITY\ANONYMOUS LOGON”. 

This happens because you’re connected using Windows authentication, and SQL Server fails to “forward” your credentials to the linked server.

To check if SQL is using Kerberos:

USE [master]
GO
SELECT      s.session_id, s.original_login_name, c.net_transport, c.auth_scheme, c.local_net_address, c.local_tcp_port, s.program_name
FROM sys.dm_exec_sessions s
LEFT OUTER JOIN sys.dm_exec_connections c on s.session_id = c.session_id
WHERE s.is_user_process = 1

To determine the authentication method of a connection, execute the following query:

SELECT net_transport, auth_scheme
FROM sys.dm_exec_connections
WHERE session_id = @@SPID;

Validating Authentication Properties Used by Connections

USE [master]
GO
SELECT COUNT(auth_scheme) as sessions_count, net_transport, auth_scheme
FROM sys.dm_exec_connections
GROUP BY net_transport, auth_scheme

 

To resolve this:

• Both SQL Servers and the Client must be in the same Domain
• Both SQL Servers must be able to register SPNs (Service Principal names)

Create SQL user and grant read-only access to a database

1. Create the Login (if it doesn’t exist)
If the login for the user hasn’t been created at the SQL Server level, you need to create it. This example assumes the user is an SQL Server authentication user.

    USE [master];
    CREATE LOGIN [new_username] WITH PASSWORD = 'your_password';

2. Grant Access to the Database
Now, switch to the database you want to grant access to and create a user associated with the login.

    USE [your_database_name];
    CREATE USER [new_username] FOR LOGIN [new_username];

3. Add the User to the db_datareader Role
Finally, add the user to the db_datareader role to provide read-only access to the database.

    ALTER ROLE [db_datareader] ADD MEMBER [new_username];

Upgrade Windows 11 Home to Windows 11 Pro

• Disable internet connection (Wi-Fi, Internet, etc.)
• Change the product key using the following Generic product key:

                VK7JG-NPHTM-C97JM-9MPGT-3V66T

• When the upgrade is completed, connect to the Internet
• Use a purchased product key to Activate the Windows

Find Windows product key using PowerShell

(Get-WmiObject -query "select * from SoftwareLicensingService").OA3xOriginalProductKey

Show SSID Password in WIndows

netsh wlan show profile

netsh wlan show profile name="SSID" key=clear

netsh wlan show profile name="SSID" key=clear | findstr Key

Finding the Manufacturing Date on Cisco Switches

switch# show version

The serial number is in this format: LLLYYWWSSSS

LLL = location of the supplier
YY = year of manufacture
WW = week of manufacture
SSSS = serial-id

Year codes:
01 = 1997
02 = 1998
03 = 1999
04 = 2000
05 = 2001
06 = 2002
07 = 2003
08 = 2004
09 = 2005
10 = 2006
11 = 2007
12 = 2008

Cannot connect to one of many SSIDs on a AP

AP has multiple SSIDs but randomly cannot connect to one SSID. The device is trying to negotiate and authenticate but cannot receive an IP address from the AP.  This can cause due to DHCP pool of available IP addresses being exhausted and there are many conflicts. To resolve the issue:

• connect to the main switch at the site
• show run | section dhcp
• clear all conflicts: clear ip dhcp conflict *
• ip dhcp pool guest_wireless
• lease for 8 hours: lease 0 8
• end
• wr
• show interface counters errors