About linux dhcp server configuration

For more information about linux dhcp server configuration-Linux general technology-Linux technology and application, see the following. Now I am referring to a document on the internet, http://www.efficient-it.com.cn/s... ce/itemid/2782.html is used to install the linux system by allocating ip addresses and tftp transfer protocol to the pxe + DHCP server driven by the network adapter.
My virtual machine virtualbox is installed with centos 6.2. According to the information, I configured the corresponding DHCP server and tftp server. However, my dhcp server configuration/etc/dhcp. confg was modified according to the data area on the Internet, and after service dhcpd restart, I found that
[Root @ NGFW ~] # Service dhcpd restart
Shutting down dhcpd: [OK]
Starting dhcpd: Internet Systems Consortium DHCP Server 4.1.1-P1
Copyright 2004-2010 Internet Systems Consortium.
All rights reserved.
For info, please visit https://www.isc.org/software/dhcp/
Not searching LDAP since ldap-server, ldap-port and ldap-base-dn were not specified in the config file
Wrote 0 class decls to leases file.
Wrote 1 leases to leases file.
Listening on LPF/eth3/08: 00: 27: 97: dc: 27/192. 168.56.0/24
Sending on LPF/eth3/08: 00: 27: 97: dc: 27/192. 168.56.0/24
Sending on Socket/fallback-net
[OK]

The startup should be successful, but I still encountered a problem during the test:


Does the above information indicate that my dhcp server is correctly configured? Although [OK] is displayed, there is still a lingering worry.
Whether the client must install the dhcp server,
What other commands are used for testing? What are the basic testing methods? Please advise.