在 CentOS6.5 上装了 DHCP 配置好之后，用 "sudo service dhcpd start" 启动报错，但是用 "sudo dhcp" 可以启动，然后查看 "/var/log/messages" 文件
Feb 3 09:12:32 dhcphost dhcpd: Internet Systems Consortium DHCP Server 4.1.1-P1
Feb 3 09:12:32 dhcphost dhcpd: Copyright 2004-2010 Internet Systems Consortium.
Feb 3 09:12:32 dhcphost dhcpd: All rights reserved.
Feb 3 09:12:32 dhcphost dhcpd: For info, please visit https://www.isc.org/software/dhcp/
Feb 3 09:12:32 dhcphost dhcpd: Not searching LDAP since ldap-server, ldap-port and ldap-base-dn were not specified in the config file
Feb 3 09:12:32 dhcphost dhcpd: Can't chown new lease file: Operation not permitted
Feb 3 09:12:32 dhcphost dhcpd:
Feb 3 09:12:32 dhcphost dhcpd: This version of ISC DHCP is based on the release available
Feb 3 09:12:32 dhcphost dhcpd: on ftp.isc.org. Features have been added and other changes
Feb 3 09:12:32 dhcphost dhcpd: have been made to the base software release in order to make
Feb 3 09:12:32 dhcphost dhcpd: it work better with this distribution.
Feb 3 09:12:32 dhcphost dhcpd:
Feb 3 09:12:32 dhcphost dhcpd: Please report for this software via the CentOS Bugs Database:
Feb 3 09:12:32 dhcphost dhcpd: http://bugs.centos.org/
Feb 3 09:12:32 dhcphost dhcpd:
Feb 3 09:12:32 dhcphost dhcpd: exiting.
其中这一行引起注意
Feb 3 09:12:32 dhcphost dhcpd: Can't chown new lease file: Operation not permitted
于是检查 /etc/rc.d/init.d/dhcpd 文件，发现其中有如下两行定义了启动dhcp的user和group
user=dhcpdgroup=dhcpd
想到上面提到的用 "sudo service dhcpd start" 不能启动而用 "sudo dhcp" 可以启动，想到可能是用户权限问题，于是把这两个参数修改为：
user=rootgroup=root
然后再使用 "sudo service dhcpd start" 启动DHCP，问题解决。