Application Layer Gateway Service (ALG) Defaults in Windows 7

Provides support for 3rd party protocol plug-ins for Internet Connection Sharing.

Default Settings

Startup type:Manual
Display name:Application Layer Gateway Service
Service name:ALG
Service type:own
Error control:normal
Object:NT AUTHORITY\LocalService
Path:%SystemRoot%\System32\alg.exe
Registry key:HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\ALG
Privileges:
  • SeChangeNotifyPrivilege
  • SeCreateGlobalPrivilege
  • SeImpersonatePrivilege

Default Behavior

Application Layer Gateway Service is a Win32 service. In Windows 7 it won't be started if the user doesn't start it. When the Application Layer Gateway Service is started, it is running as NT AUTHORITY\LocalService in its own process of alg.exe. If Application Layer Gateway Service fails to start, Windows 7 attempts to write the failure details into Event Log. Then Windows 7 startup should proceed and the user should be notified that the ALG service is not running because of the error.

Restore Default Startup Configuration for Application Layer Gateway Service

1. Select your Windows 7 edition and service pack, and then click Download.

2. Save the Win7_ALG_Service_Startup.cmd file to a local storage device.

3. Run the saved file as an administrator.

4. Restart the computer.

The ALG service is using the alg.exe file that is located in the %WinDir%\System32 folder. If the file is changed, damaged or deleted, you can restore its original version from Windows 7 installation media.