---
name: "if_mce"
section: "4"
platform: "freebsd"
package: "base"
version: "16.0-CURRENT-20261027-61c70dc16a79"
release: "FreeBSD 16.0-CURRENT (2026-10-27)"
platforms: ["freebsd"]
url: "https://new.carta.tech/if_mce"
---

# if\_mce(4)

NVIDIA Mellanox ConnectX-4/5/6 \[Dx/Ex/Lx\] based 200Gb, 100Gb, 50Gb, 40Gb, 25Gb and 10Gb ethernet adapter driver

## NAME

**mlx5en** – NVIDIA Mellanox ConnectX-4/5/6 \[Dx/Ex/Lx\] based 200Gb, 100Gb, 50Gb, 40Gb, 25Gb and 10Gb ethernet adapter driver

## SYNOPSIS

To compile this driver into the kernel, place the following lines in your kernel configuration file:

**options COMPAT\_LINUXKPI** **options RATELIMIT** **options KERN\_TLS** **device xz** **device mlxfw** **device firmware** **device mlx5** **device mlx5en**

To load the driver as a module at run-time, run the following command as root:

```
kldload mlx5en
```

To load the driver as a module at boot time, place the following lines in [loader.conf(5)](/loader.conf/5.md):

```
mlx5en_load="YES"
```

## DESCRIPTION

The **mlx5en** driver provides support for PCI Express Ethernet adapters based on ConnectX-4/5/6 \[Dx, Ex and Lx variants\]. The driver supports Jumbo Frames, Transmit and Receive checksum offload, TCP segmentation offload (TSO), Large Receive Offload (LRO), HW Large Receive Offload (HW LRO), VLAN tag insertion and extraction, VLAN checksum offload, VLAN TSO, hardware rate limiting (TXRTLMT), stateless VxLAN hardware offload for receive and transmit, HW TLS offload for transmit, Receive Side Steering (RSS) and [numa(4)](/numa/4.md) awareness.

The network interface name is mce\<N\> which corresponds to a PCI function, mlx\_core\<N\>, where \<N\> is a number starting at zero. There is at most one network interface per PCI function.

For further information and questions related to hardware requirements, see *https://www.mellanox.com*.

## HARDWARE

The **mlx5en** driver supports 200Gb, 100Gb, 50Gb, 40Gb, 25Gb and 10Gb ethernet adapters.

- ConnectX-6 supports 10/20/25/40/50/56/100Gb/200Gb/s speeds.

- ConnectX-5 supports 10/20/25/40/50/56/100Gb/s speeds.

- ConnectX-4 supports 10/20/25/40/50/56/100Gb/s speeds.

- ConnectX-4 LX supports 10/25/40/50Gb/s speeds and reduced power consumption.

## CONFIGURATION

The **mlx5en** network interface is configured using [ifconfig(8)](/ifconfig/8.md) and the [sysctl(8)](/sysctl/8.md) tree at dev.mce.\<N\>. All configurable entries are also tunables, and can be put directly into the [loader.conf(5)](/loader.conf/5.md) for persistent configuration.

## SUPPORT

For general information and support, go to the NVIDIA Mellanox networking support website at: *https://www.mellanox.com*.

If an issue is identified with this driver using a supported adapter, e-mail all the specific information related to the issue to ⟨*nbu-freebsd-drivers@nvidia.com*⟩.

## SEE ALSO

[ifconfig(8)](/ifconfig/8.md)

## HISTORY

The **mlx5en** device driver first appeared in FreeBSD 11.0.

## AUTHORS

The **mlx5en** driver was written by NVIDIA Mellanox networking \<nbu-freebsd-drivers@nvidia.com\>.