网络环境：cisco三层交换机一台，分为三个vlan 。vlan2所在网络有一台服务器，配置为http和dns服务器，还有一台主机。vlan3和vlan4各有一台主机。 实验要求： vlan3和vlan4不能相互访问，但是可以访问vlan2 下面是交换机的配置: Switch#show running-config <?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />Building configuration...Current configuration : 2428 bytes!version 12.2no service password-encryption!hostname Switch!!ip routing!!!!ip ssh version 1!port-channel load-balance src-mac!interface FastEthernet0/1switchport access vlan 2!interface FastEthernet0/2switchport access vlan 2!interface FastEthernet0/3switchport access vlan 2!interface FastEthernet0/4switchport access vlan 2!interface FastEthernet0/5switchport access vlan 2!interface FastEthernet0/6switchport access vlan 2!interface FastEthernet0/7switchport access vlan 2!interface FastEthernet0/8switchport access vlan 2!interface FastEthernet0/9switchport access vlan 3!interface FastEthernet0/10switchport access vlan 3!interface FastEthernet0/11switchport access vlan 3!interface FastEthernet0/12switchport access vlan 3!interface FastEthernet0/13switchport access vlan 3!interface FastEthernet0/14switchport access vlan 3!interface FastEthernet0/15switchport access vlan 3!interface FastEthernet0/16switchport access vlan 3!interface FastEthernet0/17switchport access vlan 4!interface FastEthernet0/18switchport access vlan 4!interface FastEthernet0/19switchport access vlan 4!interface FastEthernet0/20switchport access vlan 4!interface FastEthernet0/21switchport access vlan 4!interface FastEthernet0/22switchport access vlan 4!interface FastEthernet0/23switchport access vlan 4!interface FastEthernet0/24switchport access vlan 4!interface GigabitEthernet0/1!interface GigabitEthernet0/2!interface Vlan1no ip addressshutdown!interface Vlan2ip address 192.168.2.1 255.255.255.0!interface Vlan3ip address 192.168.3.1 255.255.255.0ip access-group 103 out!interface Vlan4ip address 192.168.4.1 255.255.255.0ip access-group 104 out!ip classless!!access-list 103 permit ip 192.168.2.0 <?xml:namespace prefix = st1 ns = "urn:schemas-microsoft-com:office:smarttags" />0.0.0.255 192.168.3.0 0.0.0.255access-list 103 permit ip 192.168.3.0 0.0.0.255 192.168.2.0 0.0.0.255access-list 104 permit ip 192.168.2.0 0.0.0.255 192.168.4.0 0.0.0.255access-list 104 permit ip 192.168.4.0 0.0.0.255 192.168.2.0 0.0.0.255!!ip dhcp pool 2network 192.168.2.0 255.255.255.0 ＃在做这里的 default-router 192.168.2.1配置可以和在windows dns-server 192.168.2.10 中配置dhcp服务器相比 ip dhcp pool 3 较下映像会更深些network 192.168.3.0 255.255.255.0default-router 192.168.3.1dns-server 192.168.2.10ip dhcp pool 4network 192.168.4.0 255.255.255.0default-router 192.168.4.1dns-server 192.168.2.10!line con 0line vty 0 4login!!end 在dhcp的客户端还要注意运用两个命令，就是ipconfig /release 和ipconfig /renew 在实验中的服务器是一个web服务器，同是也是一个dns服务器。 最后测试： PC5>ipconfig /all Physical Address................: 0090.0C6E.494A
IP Address......................: 192.168.4.2
Subnet Mask.....................: 255.255.255.0
Default Gateway.................: 192.168.4.1
DNS Servers.....................: 192.168.2.10 实验成功
