DHCP server configuration

DHCP server configuration-Linux Enterprise Application-Linux server application information. For details, refer to the following section. Configuration of the Linx DHCP server

DHCP server configuration
I. Basic concepts of DHCP
1. DHCP Definition
DHCP <动态主机配置协议> Is a seed protocol provided by TCP/IP, which works at the application layer. Provides automatically assigned IP configuration information.
2. DHCP Functions
① Dynamic Allocation (each IP Address has a lease ).
② Allocate gateway, WINS, and DNS system information.
③ Dynamic updates are implemented in combination with DNS.
④ Specify the IP address to the specific Nic.
3. DHCP Architecture
DHCP server: the host that runs the DHCP service package and DHCP protocol.
DHCP client: the host that runs the DHCP protocol to send DHCP requests.
(WIN2K, WINNT, WIN95/98/ME/XP, LINUX, UNIX)
Ii. How DHCP works
1. IP Address Allocation Process
① The CLIENT sends the broadcast DHCPDISCOVER to find the DCHP server.
② The server sends a broadcast DHCPOFFER to respond to the CLIENT's request.
③ The CLIENT checks whether the obtained IP information is complete and sends a broadcast DHCPREQUEST to notify the DHCP server that the IP address has been obtained.
④ The SERVER sends the broadcast DHCPACK to confirm the client's request, indicating that the allocation is successful.
2. Update the lease
① 50%, the CLIENT sends a DHCPREQUEST request to the server to update the lease.
② When the CLIENT sends a broadcast DHCPREQUEST to find that updates from other DHCP servers are successful, the DHCP server sends a DHCPACK message to the CLIENT if the DHCPACK fails.
Iii. DHCP service configuration
1. Install the DHCP service package
# Mount/dev/cdrom
# Cd/mnt/cdrom/RedHat/RPMS
# Ls dhcp *
# Rpm? Ivh dhcp (you can add by TAB)
Related Files And Directories:
/Var/lib/dhcp Directory: stores lease files.
/Etc/dhcpd. conf: the Core configuration file, which must be created manually.
/Var/lib/dhcp/dhcpd. lease: the database file of the customer lease.
/Etc/sysconfig/dhcpd: Configure DHCP startup parameters.
/Etc/sysconfig/dhcrelay: configure the DHCP relay proxy.
2./etc/dhcpd. conf
# Vi dhcpd. conf
Format:
Global Options (above Declaration)
Statement {
Option (valid only for declarations)
}
Option:
Global Options:
Ddns-update-style (none | ad-hoc | interim): defines the dynamic update type.
Options routers Host IP: defines the gateway.
Options domain-name-servers Host IP Address: defines the DNS server address of the client.
Options broudeast-addres: defines the broadcast address.
Options domain-name "domain name": defines the suffix domain name.
Default-lease-time number: defines the Default lease.
Max-lease-time number: defines the maximum lease time.
Common statements
Subnet network Subnet mask
{
Select
Starting IP address of Range, ending IP Address
}
Statement
Host Name {
Option host-name "host name"
Hardware Ethernet MAC address
Fixed-address IP address
}
Dhcp server configuration
# Rpm? Ivh dhcp3.op11. i386.rpm
# Vi/etc/dhcpd. conf
Ddns-update-style none;
Subnet 192.168.0.1 netmask 255.255.255.0
{
Default-lease-time 1200;
Max-lease-time 21000;
Option routers 192.168.0.1;
Option domain-man-server 211.162.0.1
Range 192.168.0.2 192.168.0.254
{
Subnet 211.162.11.0 netwask 255.255.255.0
}
}
# Touch/var/lib/dhcp/dhcpd. lease
# Vi/etc/sysconfig/dhcpd
DHCPDARGS = ETH1
#/Etc/rc. d/init. d/dhcpd restart