Security Strategies in Linux Platforms and Applications, 3rd Edition

Services

One thing init and systemd do is start up all the services. Services are autonomous ­processes that generally start up at boot time and run in the background while the ­operating system is running and operational. Another word used to describe these services that running quietly in the background is daemon. While it’s easy to think of ­services as being programs that listen for network connections, there are a number of other services in constant operation as well. In many Linux distributions—though not all—you can find all the service startup scripts in /etc/init.d/. That will tell you the ­services that you can start up on the system. Figure 3-4 shows the listing of that directory on a fairly standard install of Linux Mint, which ...