Firewall

Microsoft SQL Server can be reached via TCP/IP.

However, access must be configured in the operating system's firewall or the firewall of the antivirus solution.

Furthermore, it may be necessary to enable the server network protocol for TCP/IP.

The following script (batch file) opens the Windows Firewall for all relevant ports for Microsoft SQL Server:

@echo ========= SQL Server Ports ===================
@echo Opening SQLServer default instance port 1433
netsh firewall set portopening TCP 1433 "SQLServer"
@echo Opening dedicated SQL Admin Connection port 1434
netsh firewall set portopening TCP 1434 "SQL Admin Connection"
@echo Opening conventional SQL Server Service Broker port 4022
netsh firewall set portopening TCP 4022 "SQL Service Broker"
@echo Opening Transact-SQL Debugger/RPC port 135
netsh firewall set portopening TCP 135 "SQL Debugger/RPC"
@echo ========= Analysis Services Ports ==============
@echo Opening SSAS Default Instance port 2383
netsh firewall set portopening TCP 2383 "Analysis Services"
@echo Opening SQL Server Browser Service port 2382
netsh firewall set portopening TCP 2382 "SQL Browser"
@echo ========= Misc Applications ==============
@echo Opening HTTP port 80
netsh firewall set portopening TCP 80 "HTTP"
@echo Opening SSL port 443
netsh firewall set portopening TCP 443 "SSL"
@echo Opening port for the SQL Server Browser Service's 'Browse' button
netsh firewall set portopening UDP 1434 "SQL Browser"
@echo Allow multicast broadcast response via UDP (Browser Service Enumerations OK)
netsh firewall set multicastbroadcastresponse ENABLE

From Windows 10 or Windows Server 2012 onward:

@echo ========= SQL Server Ports ===================
@echo Opening SQLServer default instance port 1433
netsh advfirewall firewall set portopening TCP 1433 "SQLServer"
@echo Opening dedicated SQL Admin Connection port 1434
netsh advfirewall firewall set portopening TCP 1434 "SQL Admin Connection"
@echo Opening conventional SQL Server Service Broker port 4022
netsh advfirewall firewall set portopening TCP 4022 "SQL Service Broker"
@echo Opening Transact-SQL Debugger/RPC port 135
netsh advfirewall firewall set portopening TCP 135 "SQL Debugger/RPC"
@echo ========= Analysis Services Ports ==============
@echo Opening SSAS Default Instance port 2383
netsh advfirewall firewall set portopening TCP 2383 "Analysis Services"
@echo Opening SQL Server Browser Service port 2382
netsh advfirewall firewall set portopening TCP 2382 "SQL Browser"
@echo ========= Misc Applications ==============
@echo Opening HTTP port 80
netsh advfirewall firewall set portopening TCP 80 "HTTP"
@echo Opening SSL port 443
netsh advfirewall firewall set portopening TCP 443 "SSL"
@echo Opening port for the SQL Server Browser Service's 'Browse' button
netsh advfirewall firewall set portopening UDP 1434 "SQL Browser"
@echo Allow multicast broadcast response via UDP (Browser Service Enumerations OK)
netsh advfirewall firewall set multicastbroadcastresponse ENABLE

The complete documentation can be found here:

https://docs.microsoft.com/de-de/sql/sql-server/install/configure-the-windows-firewall-to-allow-sql-server-access?view=sql-server-2014