RHCE Objectives: Network services

Network services are an important subset of the exam objectives. RHCE candidates should be capable of meeting the following objectives for each of the network services listed below:

  • Install the packages needed to provide the service
  • Configure SELinux to support the service
  • Use SELinux port labeling to allow services to use non-standard ports
  • Configure the service to start when the system is booted
  • Configure the service for basic operation
  • Configure host-based and user-based security for the service


  • Synchronize time using other NTP peers

Install packages: yum install ntp, systemctl start ntpd

Configure SELinux: Should be configured out of the box; ps -e –context | grep ntp

SELinux Port labeling: Use the semanage tool to see the existing ports to be used:

semanage port -l | grep ntp

To use a different port, you’ll need to make sure the target port isn’t different

sepolicy network -p [port number]

If unreserved, then assign it.

semanage port -a -t ntp_port_t -p tcp 60123

Configure to start when booted: systemctl enable ntpd

Configure for basic operation: By default; ntpq -p to review the output.

Configure host-based and user-based security for the service:

Synchronize time using other NTP peers: Start ntpd; systemctl start ntpd. This will start the sync process. If you need to initially set your hardware clock, you can use ntpdate [servername] to manually set the date and time but ntpd can’t be running. So stop ntpd (systemctl stop ntpd), run ntpdate [servername] to sync, and then start ntpd back up (systemctl start ntpd).

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