Troubleshooting Tip: FortiOS issue with MANA Network Adapter

Description

This article describes how to proceed and resolve issues related to Azure MANA Adaptors and their integration with FortiGate VM.

Scope

FortiGate VM ('FGT VM') running FortiOS v7.6.x (v7.6.1 and later).

Solution

The Microsoft Azure Network Adapter (MANA) is a next‑generation virtual NIC that provides stable, forward‑compatible drivers for Windows and Linux VMs. Starting with FortiOS v7.6.1, FortiGate VM ('FGT VM') can use the MANA NIC on Azure Dv6/Ev6 instance types (and on later releases such as v7.6.3).

Some users experience problems after enabling MANA, for example:

• The MANA interface does not appear in diagnostic hardware information.

• BGP or VPN tunnels flap when the underlying interface is down.

• Network performance is lower than expected.

• The VM refuses to boot with 'Missing driver for network device'.

These symptoms are usually caused by missing Accelerated Networking, unsupported Azure VM size, incompatible FortiOS version, or driver initialization issues.

Below is a step-by-step checklist to verify and troubleshoot MANA integration with FortiOS.

1. Confirm FortiOS version & build. 

If the firmware is on v7.4 or below, MANA is not supported. Upgrade to v7.6.1 and above:

get system status

2. Validate Azure VM size.

The FortiGate VM must run on a supported Azure VM size that provides the MANA virtual function.

Unsupported VM sizes do not expose the MANA virtual function and will use another Azure networking driver.

3. Enable Accelerated Networking (mandatory),

Azure Accelerated Networking must be enabled for MANA operation.

Azure portal: Virtual Machine → Networking → Network Interface → Accelerated Networking → Enable.

For more information, see:

Enabling Accelerated Networking on the FortiGate VM

4. Power‑cycle the FortiGate VM.

After enabling Accelerated Networking, restart the FortiGate VM.

execute reboot (or restart from Azure)

5. Check that the MANA interface is detected inside FortiOS.
   
   

fnsysctl ifconfig

Verify that the FortiGate interfaces and the Azure accelerated networking interface are present.

The presence of sriovslv0 confirms that Azure Accelerated Networking has exposed an SR-IOV virtual function.

6. Verify the active network drivers.

To verify the active network drivers, check the synthetic interface:

diagnose hardware deviceinfo nic port1

Check the accelerated networking interface:

diagnose hardware deviceinfo nic sriovslv0

The presence of the mana driver confirms that Azure MANA is active.

7. Verify interface statistics. 

Note: No manual offload configuration is required. MANA acceleration and offload capabilities are managed automatically by the Azure MANA driver.

diagnose hardware deviceinfo nic port1

diagnose hardware deviceinfo nic sriovslv0

8. Check BGP / VPN after the NIC is up.
   
   

get router info bgp summary

diagnose vpn tunnel list

If the issue persists, contact Fortinet Support for further assistance.