使用的方法是采用DHCP方式为用户分配IP,然后限定这些用户只能使用动态IP的方式,如果改成静态IP的方式则不能连接上网络;也就是使用了DHCP SNOOPING功能。 例子: version 12.1 no service pad service timestamps debug uptime service timestamps log uptime no service password-encryption service compress-config ! hostname C4-2_4506 ! enable password xxxxxxx! clock timezone GMT 8 ip subnet-zero
no ip domain-lookup ! ip dhcp snooping vlan 180-181 // 对哪些VLAN 进行限制 ip dhcp snooping ip arp inspection vlan 180-181 ip arp inspection validate src-mac dst-mac ip
errdisable recovery cause udld errdisable recovery cause bpduguard errdisable recovery cause security-violation errdisable recovery cause channel-misconfig errdisable recovery cause pagp-flap errdisable recovery cause dtp-flap errdisable recovery cause link-flap errdisable recovery cause l2ptguard errdisable recovery cause psecure-violation errdisable recovery cause gbic-invalid errdisable recovery cause dhcp-rate-limit errdisable recovery cause unicast-flood errdisable recovery cause vmps errdisable recovery cause arp-inspection errdisable recovery interval 30 spanning-tree extend system-id ! !
interface GigabitEthernet2/1 // 对该端口接入的用户进行限制,可以下联交换机 ip arp inspection limit rate 100 arp timeout 2 ip dhcp snooping limit rate 100 !
interface GigabitEthernet2/2 ip arp inspection limit rate 100 arp timeout 2 ip dhcp snooping limit rate 100 ! interface GigabitEthernet2/3 ip arp inspection limit rate 100 arp timeout 2 ip dhcp snooping limit rate 100 ! interface GigabitEthernet2/4 ip arp inspection limit rate 100 arp timeout 2 ip dhcp snooping limit rate 100 --More--
IP Source Guard Similar to DHCP snooping, this feature is enabled on a DHCP snooping untrusted Layer 2 port. Initially, all IP traffic on the port is blocked except for DHCP packets that are captured by the DHCP snooping process. When a client receives a valid IP address from the DHCP server, or when a static IP source binding is configured by the user, a per-port and VLAN Access Control List (PACL) is installed on the port. This process restricts the client IP traffic to those source IP addresses configured in the binding. any IP traffic with a source IP address other than that in the IP source binding will be filtered out. This filtering limits a host s ability to attack the network by claiming neighbor host s IP address.