Open the firewall port for SQL Server

Windows Firewall on Windows Server 2008 helps prevent unauthorized access to computer resources. However, if the firewall is configured incorrectly, attempts to connect to an instance of SQL Server may be blocked. To access an instance of SQL Server that is behind the firewall, you must configure the firewall on the computer that is running SQL Server.

The following script is able to resolve our issue easily:

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

Rif: http://support.microsoft.com/kb/968872/en-us?fr=1