Shulou(Shulou.com)06/01 Report--

1. DHCP definition: the main function of Host dynamic configuration Protocol (Dynamic Host Configuration Protocol) is to automatically obtain IP address, subnet mask, gateway and DNS. The following is the address obtained by crawling notebook WLAN through DHCP

Wireless LAN Adapter WLAN:

Connect a specific DNS suffix. . . . . . . :

Description. . . . . . . . . . . . . . . Intel (R) Centrino (R) Wireless-N 1000

Physical address. . . . . . . . . . . . . : 8C-A9-xx-xx-xx-66

DHCP is enabled. . . . . . . . . . . : yes

Automatic configuration is enabled. . . . . . . . . . : yes

Local link IPv6 address. . . . . . . . : fe80::958a:161d:9da:f4f0%4 (preferred)

IPv4 address. . . . . . . . . . . . : 192.168.1.107 (preferred)

Subnet mask. . . . . . . . . . . . : 255.255.255.0

The time when the lease was obtained. . . . . . . . . : 18:06:32 on 16 April 2016

The time when the lease expires. . . . . . . . . : 20:06:32 on 16 April 2016

Default gateway. . . . . . . . . . . . . : 192.168.1.1

DHCP server. . . . . . . . . . . : 192.168.1.1

DHCPv6 IAID. . . . . . . . . . . : 76327298

DHCPv6 client DUID. . . . . . . : 00-01-00-01-1E-3C-E6-6B-F0-DE-xx-xx-xx-xx

2. DHCP experiments and DHCP applications are very common, which generally don't cause too many problems and don't involve too much deep content.

(1) when the host is connected to the VLAN of a switch, if the host is not configured with an IP address, the host system will automatically send a DHCP broadcast request, and the gateway accepts the DHCP request and forwards it on its behalf to obtain address communication.

(2) if the DHCP server is not in the same network segment as your host, the gateway will forward the request to the DHCP server through the relay address. A conceptual DHCP relay is involved here, which is intended to forward requests across network segments.

(3) four packages of DHCP

PC-DHCPDISCOVERY-- > (DHCP SERVER) # send DHCP request packet

PC (DHCP SERVER) # get an available address

PC-DHCPACK- > (DHCP SERVER) # confirm the address received

(3) experiment 1

PC1 and PC2 are connected to the switch F0swap 1 and F0Blue2 respectively (the default is to keep it in the same VLAN1, and I use VLAN1 as the management VLAN in many places), and PC1 and PC2 are set to DHCP to obtain the address respectively.

The switch configuration script is as follows:

En

Conf t

Int vlan 1

Des gw

Ip add 172.16.1.250 255.255.255.0

No shut

Service dhcp

Ip dhcp pool dhcpserver

Network 172.16.1.0 255.255.255.0 # announces network segment

Default-router 172.16.1.1 # Gateway

Dns-server 8.8.8.8 # DNS

Exit

Ip dhcp excluded-address 192.168.1.250 # exclude this segment gateway, otherwise this address may be assigned

End

Wr mem

Check the PC address acquisition:

The experimental 2:DHCP relay is switched to Huawei ENSP simple configuration. The Cisco PT simulator does not support the simulator at present.

Sys

Dhcp server group 1

Dhcp-server 172.21.x.1 0 # this address is the server address

Vlan 10

Quit

Interface Vlan10

Ip add 172.16.1.1 24

Dhcp select relay

Dhcp relay server-select 1 # calls the IP address set by the DHCP group

Return

Save

The experiment is over.

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