Application Layer Gateway Service (ALG) Defaults in Windows 8

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

The Application Layer Gateway Service is a Win32 program that can be started by the Service Controller and that obeys the service control protocol. In Windows 8 it will not be started until the user starts it. When the Application Layer Gateway Service is started, it runs as NT AUTHORITY\LocalService in its own process of alg.exe. If Application Layer Gateway Service fails to start, the error details are added to Windows 8 error log. When the operating system startup is complete, the user is being notified that the ALG service hasn't been started.

Restore Default Startup Configuration for Application Layer Gateway Service

1. Run the Command Prompt as an administrator.

2. Copy the command below, paste it into the command window and press ENTER:

sc config ALG start= demand

3. Close the command window and restart the computer.

The ALG service is using the alg.exe file that is located in the %WinDir%\System32 folder. If the file is corrupted or deleted, you can put it back in there.