Keep Azure public addresses out of guest IP configuration

Source facts

Azure translates a VM’s private address to its assigned public address. Microsoft says the guest is unaware of that public address and it should not be manually entered in the operating system’s IP configuration.

Private multi-address configuration has different requirements. Microsoft’s guidance calls for manually setting primary and secondary addresses in Windows when adding multiple IPs; for Linux, it calls for configuring the secondary addresses. Microsoft Learn.

Applicability

Inventory each Azure NIC IP configuration, its private address, any associated public-address resource, and the guest operating system. Review the current OS-specific procedure before editing the adapter, especially for an existing multi-address deployment.

DSE recommendation

DSE recommends an address mapping that clearly separates Azure public resources from guest private addresses. Have the network owner approve the mapping and retain an alternate management path before changing a live adapter. Do not copy a portal’s public address into the guest to troubleshoot an unrelated connectivity failure.

Verification

After an approved test change, compare Azure’s private IP assignments with the guest configuration and exercise each intended application binding. Check inbound and outbound behavior through the expected Azure path separately. Preserve the mapping and observed results, and investigate any discrepancy before applying the procedure to additional machines.

Official references

Microsoft Learn: Configure IP addresses for an Azure network interface. Source retrieved September 9, 2026.