4 urpf troubleshooting, 5 arp, 1 introduction to arp – PLANET XGS3-24040 User Manual

Page 189: 2 arp configuration task list

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Chapter 21 Layer 3 Forward Configuration

21-19

SW3 configuration task sequence:

Switch3#config

Switch3(config)#urpf enable

Switch3(config)#interface ethernet 3/3

Switch3(Config-If-Ethernet3/3)#ip urpf enable strict

21.4.4 URPF Troubleshooting

Proper operation of the URPF protocol depends greatly on whether the corresponding URPF rules can be

applied correctly. If after the URPF configuration is done and the function does not meet the expectation:

 Check if the switch has been configured with the rules conflicting with URPF (URPF priority is lower

than ACL), the ACL rules will validate if confliction exits.

 Check whether there is a relative route in the FIB table. Only when one is found, can the ACL rules be

distributed to the port.

 Check if the hardware ACL performance is full which lead to the newly generated route can not be

applied with ACL rules.

 If all configurations are normal but URPF still can’t operate as expected, please enable the URPF

debug function and use the “show urpf” command and other commands which display the rule number

and details to observe whether the created URPF rules are correct, and send the result to the

technology service center.

21.5 ARP

21.5.1 Introduction to ARP

ARP (Address Resolution Protocol) is mainly used to resolve IP address to Ethernet MAC address. Switch

supports both dynamic ARP and static ARP configuration.Furthermore, switch supports the configuration of

proxy ARP for some applications. For instance, when an ARP request is received on the port, requesting an IP

address in the same IP segment of the port but not the same physical network, if the port has enabled proxy

ARP, the port would reply to the ARP with its own MAC address and forward the actual packets received.

Enabling proxy ARP allows machines physically separated but of the same IP segment ignores the physical

separation and communicate via proxy ARP interface as if in the same physical network.

21.5.2 ARP Configuration Task List

ARP Configuration Task List:

1. Configure static ARP

2. Configure proxy ARP

3. Clear dynamic ARP

4. Select hash arithmetic

5. Clear the statistic information of ARP messages

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