When the DHCP snooping function is enabled on the wireless controller, network devices or terminals that communicate with the wireless controller at Layer 2 cannot obtain IP addresses.
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Network Topology
none
Problem Description
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Announcement category |
early warning |
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operating requirements |
learning prevention |
Product Number:
Comware V7 platform wireless controller products
Related Version:
Versions earlier than R5441P01 (not included)
Problem Description:
When the DHCP snooping function is enabled on the wireless controller, network devices or terminals that communicate with the wireless controller at Layer 2 cannot obtain IP addresses.
Process Analysis
When the wireless controller enables the DHCP Snooping function and receives a DHCP DISCOVER message in the network, due to a software problem in this function, the wireless controller will copy the message and return it according to the original path, resulting in the MAC address of the intermediate network device Abnormal learning, such as MAC address drift, and then the terminal or network device cannot obtain the IP address.
Solution
1) Disable the DHCP Snooping function on the AC side to avoid it temporarily. The command is as follows: undo dhcp snooping enable.
2) Upgrading the wireless controller version to R5441P01 and above can completely solve the problem.