DCHP Servers
Dynamic Host Configuration Protocol (DHCP) is a network protocol that automatically assigns TCP/IP information to client machines. Each DHCP client connects to the centrally located DHCP server, which returns the network configuration (including the IP address, gateway, and DNS servers) of that client.
Why Use DHCP?
DHCP is useful for automatic configuration of client network interfaces. When configuring the client system, you can choose DHCP instead of specifying an IP address, netmask, gateway, or DNS servers. The client retrieves this information from the DHCP server. DHCP is also useful if you want to change the IP addresses of a large number of systems. Instead of reconfiguring all the systems, you can just edit one configuration file on the server for the new set of IP addresses. If the DNS servers for an organization changes, the changes happen on the DHCP server, not on the DHCP clients. When you restart the network or reboot the clients, the changes go into effect. If an organization has a functional DHCP server correctly connected to a network, laptops and other mobile computer users can move these devices from office to office.
Configuring A DHCP Server
[root@xlnx-lab05 ~]# cat /etc/redhat-release Red Hat Enterprise Linux Server release 7.0 (Maipo)
[root@xlnx-lab05 ~]# yum -y install dhcp
Configuration File
[root@xlnx-lab05 ~]# cat /etc/dhcp/dhcpd.conf
#
# DHCP Server Configuration file.
# see /usr/share/doc/dhcp*/dhcpd.conf.example
# see dhcpd.conf(5) man page
#
ddns-update-style none;
ignore client-updates;
subnet 192.168.1.0 netmask 255.255.255.0{
range 192.168.1.100 192.168.1.120;
option subnet-mask 255.255.255.0;
option routers 192.168.1.254;
option domain-name-servers 8.8.8.8;
default-lease-time 21600;
max-lease-time 43200;
}
[root@xlnx-lab05 ~]# systemctl restart dhcpd
[root@xlnx-lab05 ~]# systemctl enable dhcpd
[root@xlnx-lab05 ~]# systemctl status dhcpd
dhcpd.service - DHCPv4 Server Daemon
Loaded: loaded (/usr/lib/systemd/system/dhcpd.service; enabled)
Active: active (running) since Tue 2020-03-24 01:17:01 CST; 8s ago
Docs: man:dhcpd(8)
man:dhcpd.conf(5)
Main PID: 35428 (dhcpd)
CGroup: /system.slice/dhcpd.service
└─35428 /usr/sbin/dhcpd -f -cf /etc/dhcp/dhcpd.conf -user dhcpd -group dhcpd --no-pid
Mar 24 01:17:01 xlnx-lab05 systemd[1]: Started DHCPv4 Server Daemon.
Mar 24 01:17:01 xlnx-lab05 dhcpd[35428]: Internet Systems Consortium DHCP Server 4.2.5
Mar 24 01:17:01 xlnx-lab05 dhcpd[35428]: Copyright 2004-2013 Internet Systems Consortium.
Mar 24 01:17:01 xlnx-lab05 dhcpd[35428]: All rights reserved.
Mar 24 01:17:01 xlnx-lab05 dhcpd[35428]: For info, please visit https://www.isc.org/software/dhcp/
Mar 24 01:17:01 xlnx-lab05 dhcpd[35428]: Not searching LDAP since ldap-server, ldap-port and ldap-base-dn were not specified in the config file
Mar 24 01:17:01 xlnx-lab05 dhcpd[35428]: Wrote 1 leases to leases file.
Mar 24 01:17:01 xlnx-lab05 dhcpd[35428]: Listening on LPF/eth0/00:0c:29:ad:b8:84/192.168.1.0/24
Mar 24 01:17:01 xlnx-lab05 dhcpd[35428]: Sending on LPF/eth0/00:0c:29:ad:b8:84/192.168.1.0/24
Mar 24 01:17:01 xlnx-lab05 dhcpd[35428]: Sending on Socket/fallback/fallback-net
[root@xlnx-lab05 ~]# ip a s
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 00:0c:29:ad:b8:84 brd ff:ff:ff:ff:ff:ff
inet 192.168.1.5/24 brd 192.168.1.255 scope global eth0
valid_lft forever preferred_lft forever
inet6 fe80::20c:29ff:fead:b884/64 scope link
valid_lft forever preferred_lft forever
[root@xlnx-lab05 ~]# route -n
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
0.0.0.0 192.168.1.254 0.0.0.0 UG 1024 0 0 eth0
192.168.1.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0
Windows Host
C:\Users\Xilong Jin>ipconfig /all Windows IP Configuration Host Name . . . . . . . . . . . . : PC01 Primary Dns Suffix . . . . . . . : Node Type . . . . . . . . . . . . : Hybrid IP Routing Enabled. . . . . . . . : No WINS Proxy Enabled. . . . . . . . : No Ethernet adapter Ethernet0: Connection-specific DNS Suffix . : Description . . . . . . . . . . . : Intel(R) 82574L Gigabit Network Connection Physical Address. . . . . . . . . : 00-0C-29-1F-43-7C DHCP Enabled. . . . . . . . . . . : Yes Autoconfiguration Enabled . . . . : Yes IPv4 Address. . . . . . . . . . . : 192.168.1.100(Preferred) Subnet Mask . . . . . . . . . . . : 255.255.255.0 Lease Obtained. . . . . . . . . . : Tuesday, March 24, 2020 1:03:01 AM Lease Expires . . . . . . . . . . : Tuesday, March 24, 2020 7:03:01 AM Default Gateway . . . . . . . . . : 192.168.1.254 DHCP Server . . . . . . . . . . . : 192.168.1.5 DNS Servers . . . . . . . . . . . : 8.8.8.8 NetBIOS over Tcpip. . . . . . . . : Enabled
MAC Address Binding
Reterive Mac Addr
[root@xlnx-lab05 ~]# tail -F /var/log/messages Mar 24 01:20:50 xlnx-lab05 dhcpd: DHCPREQUEST for 192.168.1.100 from 00:0c:29:1f:43:7c (PC01) via eth0 Mar 24 01:20:50 xlnx-lab05 dhcpd: DHCPACK on 192.168.1.100 to 00:0c:29:1f:43:7c (PC01) via eth0
[root@xlnx-lab05 ~]# cat /etc/dhcp/dhcpd.conf
#
# DHCP Server Configuration file.
# see /usr/share/doc/dhcp*/dhcpd.conf.example
# see dhcpd.conf(5) man page
#
ddns-update-style none;
ignore client-updates;
subnet 192.168.1.0 netmask 255.255.255.0{
range 192.168.1.100 192.168.1.120;
option subnet-mask 255.255.255.0;
option routers 192.168.1.254;
option domain-name-servers 8.8.8.8;
default-lease-time 21600;
max-lease-time 43200;
host yufengc{
hardware ethernet 00:0c:29:1f:43:7c;
fixed-address 192.168.1.118;
}
}
[root@xlnx-lab05 ~]# systemctl restart dhcpd
[root@xlnx-lab05 ~]# systemctl enable dhcpd
Windows Host
Microsoft Windows [Version 10.0.18362.30] (c) 2019 Microsoft Corporation. All rights reserved. C:\Users\Xilong Jin>ipconfig /all Windows IP Configuration Host Name . . . . . . . . . . . . : PC01 Primary Dns Suffix . . . . . . . : Node Type . . . . . . . . . . . . : Hybrid IP Routing Enabled. . . . . . . . : No WINS Proxy Enabled. . . . . . . . : No Ethernet adapter Ethernet0: Connection-specific DNS Suffix . : Description . . . . . . . . . . . : Intel(R) 82574L Gigabit Network Connection Physical Address. . . . . . . . . : 00-0C-29-1F-43-7C DHCP Enabled. . . . . . . . . . . : Yes Autoconfiguration Enabled . . . . : Yes IPv4 Address. . . . . . . . . . . : 192.168.1.118(Preferred) Subnet Mask . . . . . . . . . . . : 255.255.255.0 Lease Obtained. . . . . . . . . . : Tuesday, March 24, 2020 1:29:55 AM Lease Expires . . . . . . . . . . : Tuesday, March 24, 2020 7:29:55 AM Default Gateway . . . . . . . . . : 192.168.1.254 DHCP Server . . . . . . . . . . . : 192.168.1.5 DNS Servers . . . . . . . . . . . : 8.8.8.8 NetBIOS over Tcpip. . . . . . . . : Enabled
来源：https://www.cnblogs.com/xilongj/p/12556352.html