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VTNET(4)              DragonFly Kernel Interfaces Manual              VTNET(4)


vtnet -- VirtIO Ethernet driver


To compile this driver into the kernel, place the following lines in your kernel configuration file: device vtnet Alternatively, to load the driver as a module at boot time, place the following line in loader.conf(5): if_vtnet_load="YES"


The vtnet device driver provides support for VirtIO Ethernet devices. If the hypervisor advertises the appreciate features, the vtnet driver supports TCP/UDP checksum offload for both transmit and receive, TCP segmentation offload (TSO), TCP large receive offload (LRO), and hardware VLAN tag stripping/insertion features, as well as a multicast hash filter, as well as Jumbo Frames (up to 9216 bytes), which can be configured via the interface MTU setting. Selecting an MTU larger than 1500 bytes with the ifconfig(8) utility configures the adapter to receive and transmit Jumbo Frames. For more information on configuring this device, see ifconfig(8).


Tunables can be set at the loader(8) prompt before booting the kernel or stored in loader.conf(5). hw.vtnet.csum_disable This tunable disables receive and send checksum offload. The default value is 0. hw.vtnet.tso_disable This tunable disables TSO. The default value is 1. hw.vtnet.lro_disable This tunable disables LRO. The default value is 0.


arp(4), ifmedia(4), netintro(4), ng_ether(4), virtio(4), vlan(4), ifconfig(8)


The vtnet driver was written by Bryan Venteicher <bryanv@FreeBSD.org>. It first appeared in FreeBSD 9.0.


The vtnet driver only supports LRO when the hypervisor advertises the mergeable buffer feature. The receive checksum offload feature of the vtnet driver is masked for now, because of missing support for receive checksum offload in IPv6 packet handling in DragonFly. DragonFly 4.9 October 17, 2017 DragonFly 4.9

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