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Chapter 24. DHCP
The
dhcpd
daemon is used in Red Hat Enterprise Linux to dynamically deliver and configure Layer 3 TCP/IP details for clients.
The dhcp package provides the DHCP server and the
dhcpd
daemon. Enter the following command to see if the dhcp package is installed:
~]# rpm -q dhcp package dhcp is not installed
~]# rpm -q dhcp
package dhcp is not installed
If it is not installed, use the
yum
utility as root to install it:
~]# yum install dhcp
~]# yum install dhcp
24.1. DHCP and SELinux
When
dhcpd
is enabled, it runs confined by default. Confined processes run in their own domains, and are separated from other confined processes. If a confined process is compromised by an attacker, depending on SELinux policy configuration, an attacker's access to resources and the possible damage they can do is limited. The following example demonstrates dhcpd
and related processes running in their own domain. This example assumes the dhcp package is installed and that the dhcpd
service has been started:
- Run the
getenforce
command to confirm SELinux is running in enforcing mode:~]$ getenforce Enforcing
~]$ getenforce Enforcing
Copy to Clipboard Copied! The command returnsEnforcing
when SELinux is running in enforcing mode. - Enter the following command as the root user to start
dhcpd
:~]# systemctl start dhcpd.service
~]# systemctl start dhcpd.service
Copy to Clipboard Copied! Confirm that the service is running. The output should include the information below (only the time stamp will differ):~]# systemctl status dhcpd.service dhcpd.service - DHCPv4 Server Daemon Loaded: loaded (/usr/lib/systemd/system/dhcpd.service; disabled) Active: active (running) since Mon 2013-08-05 11:49:07 CEST; 3h 20min ago
~]# systemctl status dhcpd.service dhcpd.service - DHCPv4 Server Daemon Loaded: loaded (/usr/lib/systemd/system/dhcpd.service; disabled) Active: active (running) since Mon 2013-08-05 11:49:07 CEST; 3h 20min ago
Copy to Clipboard Copied! - Run following command to view the
dhcpd
processes:~]$ ps -eZ | grep dhcpd system_u:system_r:dhcpd_t:s0 5483 ? 00:00:00 dhcpd
~]$ ps -eZ | grep dhcpd system_u:system_r:dhcpd_t:s0 5483 ? 00:00:00 dhcpd
Copy to Clipboard Copied! The SELinux context associated with the dhcpd process issystem_u:system_r:dhcpd_t:s0
.