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Chapter 13. DHCP

DHCPD is the daemon 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, dhcpd. Run the rpm -q dhcp command to see if the dhcp package is installed. If it is not installed, run the following command as the root user to install it:
~]# yum install dhcp

13.1. 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 the 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:
  1. Run the getenforce command to confirm SELinux is running in enforcing mode:
    ~]$ getenforce
    The getenforce command returns Enforcing when SELinux is running in enforcing mode.
  2. Run the service dhcpd start command as the root user to start DHCPD:
    ~]# service dhcpd start
    Starting dhcpd:                               [  OK  ]
  3. Run the ps -eZ | grep dhcpd command to view the dhcpd processes:
    ~]$ ps -eZ | grep dhcpd
    unconfined_u:system_r:dhcpd_t:s0 5483 ?        00:00:00 dhcpd
    The SELinux context associated with the dhcpd process is unconfined_u:system_r:dhcpd_t:s0.