How to disable unnecessary system services in Linux

Taking redhat9 as an example, most of the following system services can be shut down:
Cron (depending on the situation, sometimes required)
Anancron
Apmd
ATD
Autofs
Cups (with a printer)
GPM
ISDN
Kudzu
Netfs
Nfslock
PCMCIA
Portmap
Rawdevice
Rhnsd
Sendmail (you can disable the email server)
IPSec (without configuration, it does not provide security at all)
... There are some more, which are not listed here.
Redhat9.0 on my computer only starts the following system services
Vmware-tools (Virtual Machine)
Syslog (logging)
Network)
Randow (Protection)
Keytables (Extended keyboard)
Iptables (firewall on Linux)
XFS (Graphic window)
Xinetd (Super process, providing network services externally)
In this way, the boot speed is quite fast.
You can modify the service in two ways:
1. chnconfig command:
Use chkconfig -- list to check whether all system services are disabled or enabled.
Use chkconfig iptables on to set a random start service
Use chkconfig iptables off to set the service to be started randomly
2. Use setup to start the graphic setting tool to set whether or not to start the service randomly.
Note: This modification takes effect only after the machine is restarted. If you only need a service this time, but do not
Yes. You can use service start to start the service manually.
In/etc/syslog, the configuration file of the System Service has the same name as the executable file of the service. The service reads the configuration file to provide the service and can modify the configuration file to customize the service. For example, in/etc/syslog, the configuration file iptables with iptables stores firewall rules and denies access from other IP addresses to the local machine.