PXE booting is failing intermittently for DHCP server and client on NSX segment
Article ID: 422179
Updated On:
Products
VMware NSX
Issue/Introduction
- Existing Virtual Machines on NSX segments fail to obtain IP address during EFI network PXE boot from third-party DHCP server.
- The DHCP server and Virtual Machines are both on overlay segments.
- Not all Virtual Machines are impacted at the same time.
- Newly deployed Virtual Machines or Virtual Machines with fresh vNICs (new MAC address) boot successfully.
- Packet captures at DHCP server VM level confirms that the DHCP Offer is sent out.
- Packet capture at DHCP client VM confirms the DHCP Offer is received.
Environment
VMware NSX
Cause
- The DHCP offer received by the VM does not contain a file-server host name (Option 66) or boot file name (Option 67). So the client re-sends a DHCP Discover.
- Without these options, the PXE client cannot identify the DHCP server or the file to download, causing it to reject the offer and retry discovery.
Resolution
- Verify the DHCP Offer received by the client VM contains all required parameters (e.g. Option 66 and 67).
- Engage with the DHCP server vendor to review configuration for reservations and lease management.
Workaround: A new vNIC or MAC address will typically trigger a fresh DHCP Offer from the server.
- Connect a new vNIC to the VM.
- Change the MAC address of the existing vNIC.
Additional Information
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