Integrated use of DHCP and VLANs (CISCO)

Cisco's DHCP and VLAN synthesis experiment

Experimental content:

PC1 and PC2 need to obtain an IP address through DHCP Server . R1 do one-arm routing and DHCP Relay,R2 interface f2/0 IP address is 192.168.3.1. and PC1 belongs to Vlan10,PC2 belongsto Vlan20,R3(DHCP Server ) belongs to VLAN30.

PC1 belongs to 192.168.1.0 network segment, Gateway is 192.168.1.254 PC2 belongs to 192.168.2.0 network segment, Gateway is 192.168.2.254

Extension and Repair map:

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Experimental ideas:

1. in the VLAN 10,20,30 is configured on the S1, and the E0/2 port is a trunk port

2. R1 to Create a sub-interface for the VLAN30. And each sub-interface specifies the encapsulation mode and the IP address of the specified DHCP Server .

3. The default route to the host needs to be configured on the DHCP Server

Experiment Configuration:

s1 (config) #vlan  10 s1 (Config-vlan) #vlan  20s1 (Config-vlan) #vlan  30s1 (Config-vlan) #do  show vlan   See if it is created and is active S1 (config) #interface   ETHERNET 0/0S1 (config-if) #switchport  access vlan 10s1 (config-if) #inter  e0/1s1 ( CONFIG-IF) #swi  acc vlan 20s1 (config-if) #inter  e0/3s1 (config-if) #swi  ac vlan  30S1 (config-if) #inter  e0/2s1 (config-if) #switchport  trunk encapsulation dot1q    Note Don't forget this step S1 (config-if) #switchport  mode trunk 

s1 (config-if) #do  show inter e0/2 switchport     See if 0/2 ports are trunk port R1 (config) #interface  fastethernet 0/0.1r1 (config-subif) #encapsulation  dot1Q 10     Specifies the encapsulation mode and the VlanR1 (CONFIG-SUBIF) #ip for the sub-interface  add 192.168.1.254  255.255.255.0R1 (config-subif) #ip  helper-address 192.168.3.1     Specify DHCP  server IP address (relay Agent) R1 (config) #interface  fastethernet 0/0.2r1 (config-subif) #encapsulation   Dot1q 20 

r1 (config-subif) #ip  add 192.168.2.254 255.255.255.0r1 ( CONFIG-SUBIF) #ip  helper-address 192.168.3.1  r1 (config) #interface  fa0/0.3r1 ( CONFIG-SUBIF) #encapsulation  dot1Q 30     Note: Here to create a sub-interface for Dhcp server R1 ( CONFIG-SUBIF) #ip  add 192.168.3.254 255.255.255.0r1 (config-subif) #inter  fa0/0 r1 ( CONFIG-IF) #no  shutdown r2 (config) #ip  dhcp excluded-address 192.168.1.200  192.168.1.255r2 (config) #ip  dhcp excluded-address 192.168.2.200 192.168.2.255r2 (config) #ip  DHCP POOL PC1 

R2 (dhcp-config) #network  192.168.1.0 255.255.255.0r2 (dhcp-config) #default-ROUTER 192.168.1.254R2 (dhcp-config) #dns-server 8.8.8.8r2 (dhcp-config) #lease  2 3 4r2 (config) #ip  dhcp  POOL PC2R2 (dhcp-config) #network  192.168.2.0 255.255.255.0r2 (dhcp-config) #default-router  192.168.2.254R2 (dhcp-config) #dns-server 8.8.8.8r2 (dhcp-config) #lease  2 3 4r2 (config) #ip  route 0.0.0.0 0.0.0.0 192.168.3.254     Configure a default route to the host (otherwise PC gets ip                                                                                          failed) R2 (config) #inter  fa2/0r2 (config-if) #ip  add  192.168.3.1 255.255.255.0R2 (config-if) #no  sh

Experimental validation:

Start PC1 no IP address

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PC1 use DHCP to obtain an IP address:

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PC1 successfully acquired the IP address:

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This article from "I-Rookie" blog, declined reproduced!

Integrated use of DHCP and VLANs (CISCO)