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Version: v25.07.31

DHCP Troubleshooting

This document explains how to fix issues with DHCP on CE devices. DHCP is a system that automatically assigns IP addresses to devices and connects them to a network, making it easier to manage a network. When DHCP is not working, devices can disconnect from the network. This guide will help you check if DHCP is working properly and find possible issues on CE devices.

Troubleshooting Steps​

Cloud Configuration Verification​

This section details how to check the configurations made in the cloud. The commands below can be used to verify the cloud configuration.

Access the CE Terminal​

Log into the CE device and gain root access:

sudo su -

Verify DHCPv2 Configuration​

If the device implements DHCPv2, examine its current settings. This command displays the most recently configured settings, as shown in the example response.

cat /tmp/last_config_response.json | jq '.service.dhcpV2'

The given one is just an example output; when this command is run, it will show something like this.

Example Response​

{
  "eth3": {
    "sharedNetworkName": "dhcpServer_eth3",
    "subnet": "172.10.2.0/24",
    "dnsServer": "172.10.2.1",
    "defaultRouter": "172.10.2.1",
    "dhcpRanges": [
      {
        "start": "172.10.2.51",
        "stop": "172.10.2.101"
      }
    ]
  }
}

This command will extract and display the last configuration response using DHCPv2 configuration.

Q:1 How can I verify if DHCPv2 configuration is applied on the device?

Run the command: cat /tmp/last_config_response.json | jq '.service.dhcpV2'. If the output displays DHCPv2 details (such as subnet, DNS server, default router, and ranges), it means the configuration has been applied. Additionally, check if client devices connected to the LAN are receiving IPs within the defined DHCP range — this confirms the configuration is active.

Q:2 What should I check in the DHCPv2 response to confirm correct configuration?

Verify the following key fields in the JSON output: subnet → Ensure it matches the intended network (e.g., 172.10.2.0/24). dnsServer → Confirm it points to the correct DNS server (often the gateway). defaultRouter → Should match the gateway IP for the subnet. dhcpRanges → Check that the start and stop IPs are within the subnet and correctly defined (e.g., 172.10.2.51 to 172.10.2.101). If all these values align with your intended configuration, the DHCPv2 setup is correct.

Q:3 What if the file /tmp/last_config_response.json is missing?

If the file is missing, it means the device has not yet received or saved the latest cloud configuration. Steps to resolve: Ensure the CE device is online and properly synced with the cloud controller. Trigger a configuration push from the cloud management platform. Check logs (/var/log/) to confirm if configuration updates are being received. If the file still doesn’t appear, restart the CE device or reapply the configuration from the cloud.