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[Case Show] Static-IP-address PC Under a Bridging ONT Fails to Visit the Interne

Ken_liu Gold Huawei Staff

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6 years 11 months ago View: 1062 Reply: 0

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Fault Category

Internet access service

Symptom

Network topology: OLT (MA5603T) -> ONT (HG8245T) -> PC

Version: OLT V800R010C00

The HG8245T is a bridging ONT, which uses a LAN port to connect to the PC. The PC is configured with a static IPv4 address. Configurations on the MA5603T are correct, including the S-VLAN, ONT line profile, ONT service profile, and service port. After MAC anti-spoofing (global-level and VLAN-level) is enabled on the MA5603T, the PC fails to visit the upper-layer network. After the display arp dynamic command is executed to query ARP entries, it is found that the MAC address of the PC is not learned.

Alarm Information

None

Cause Analysis

The MA5603T implements MAC anti-spoofing based on the following schemes:

After MAC anti-spoofing is enabled, the MA5603T stops dynamic MAC address learning, captures DHCPv4 and PPPoE packets from both the user and network side, dynamically obtains the source MAC address, and sets the binding relationship between the source MAC address and the user port or between the source MAC address and the service flow.
After MAC anti-spoofing is disabled, the MA5603T resumes dynamic MAC address learning and no longer captures PPPoE or DHCPv4 packets from the user or network side. The MA5603T also deletes its MAC address binding entries.

According to these two schemes, after being enabled with MAC anti-spoofing, the MA5603T does not send DHCP or PPPoE packets because the PC is configured with a static IP address. However, the MA5603T disables MAC address learning. Therefore, the MA5603T does not learn the MAC address of the PC and the PC fails to visit the Internet.

Procedure

If this fault occurs, perform the following operations according to actual conditions:

Disable MAC-anti-spoofing.
Run the arp command to add the MAC address of the PC to the ARP entry.
Set the mode for the PC to obtain the IP address to DHCP or PPPoE.

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