alg.exe(Application Layer Gateway service) is a process belonging to Microsoft Windows Operating System. It is a core process for Microsoft Windows Internet Connection sharing and Internet connection firewall. This program is important for the stable and secure running of your computer and should not be terminated. It is required if you use a 3rd party firewall or Internet Connection Sharing (ICS) to connect to the internet. Do not end this program in task manager - you will lose all internet connectivity until next restart or login.
The alg.exe file is located in the folder C:\Windows\System32. In other cases, alg.exe is a virus, spyware, trojan or worm.