Review the ARP configuration of the Cisco Router

In addition to address binding, ARP configurations of Cisco routers are getting more and more attention. Therefore, we will discuss two aspects here. It seems a bit messy, but I hope it will help you. I know that the command for binding the IP address of the cisco router to the mac address is arp IP address, mac address, arpa, but I think there should be a command that shows the start binding command. for example, the IP address in any CIDR block can be above before the vro is configured for binding, until the binding command is displayed.

The IP address and network card hardware address bound to a CISCO switch or vro. the MAC address of the network card is usually the only one. Create a table for the corresponding IP address and MAC address in the vro, only the legitimate IP-MAC address corresponding to the registered machine can get the correct Cisco router ARP response, to control the IP-MAC does not match the host and the external communication, to prevent IP address theft. For example, if the IP address of a LAN user is 202.196.191.190 and the MAC address is 0010.40bc.b54e, run the following command on the route module of the Cisco router or switch: router (config) # arp 202.196.191.190 0010.40bc. B

Bind the IP address to the MAC address. If someone steals the IP address, the IP address fails to be stolen because of its uniqueness. for unassigned IP addresses, We can bind them with a MAC address, for example, 2.16.0000.0000, so that they are not stolen. for example, if 202.196.190.119 is not used, bind it with the following command. router (config) # arp 202.196.191.190 2.16.0000.0000 arpa

Conclusion: Using MAC addresses and IP addresses can effectively prevent IP addresses from being stolen. Although it is troublesome to collect users' MAC addresses in the early stage, however, the establishment of such a mechanism can bring a lot of convenience for users to manage the network. Therefore, we should collect the MAC address information of machines in the LAN at the initial stage of building the network to facilitate our future network management work!

For Windows 98/Me, Run "winipcfg". The IP address displayed in the dialog box is, and the "adapter address" is the MAC address of the NIC. For Windows 2000/XP, enter "ipconfig/all" at the command prompt ". In the displayed list, "Physical Address" is the MAC Address, and "IP Address" is the IP Address. to bind the two, enter "arp-s your IP Address, your MAC Address ", for example, "ARP-s 192.168.1.5 80-00-0B-B4-36-70 ".

Question: How can I configure static ARP on a Cisco router to make a permanent ing between a layer-3 IP address and a layer-2 MAC address?

Answer: configure the Cisco router ARP address ing on the Cisco router and run the arp ip-address hardware-address type [alias] command to remove the static ARP address ing, run the no arp ip-address hardware-address type [alias] command. The parameters are described as follows: ip-address 32-bit ip address. hardware-address: 48-bit MAC address. type encapsulation type. for Ethernet interfaces, it is generally of the arpa type. the FDDI and ring-based interfaces are usually of the snap type. alias (Optional) indicates that when a vro discovers that it has the requested address, the Cisco IOS software will respond to the Cisco router ARPrequests.