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Differences between venet and veth

Revision as of 13:05, 24 February 2010 by 64.65.78.18 (talk)

OpenVZ provides veth (Virtual eTHernet) or venet (Virtual NETwork) devices (or both) for in-CT networking. Here we describe the differences between those devices.

  • veth allows broadcasts in CT, so you can use even a DHCP server inside a CT, or a samba server with domain broadcasts or other such stuff.
  • veth has some security implications. It is normally bridged directly to the host physical ethernet device and so must be treated with the same considerations as a real ethernet device on a standalone host. The CT users can access a veth device as they would a real ethernet interface. However, the CT root user is the only one that has priviledged access to the veth device.
  • With venet device, only OpenVZ host node administrator can assign an IP to a CT. With veth device, network settings can be fully done on CT side by the CT administrator. CT should setup correct gateway, IP/netmask etc. and then a node admin can only choose where your traffic goes.
  • veth devices can be bridged together and/or with other devices. For example, in host system admin can bridge veth from 2 CTs with some VLAN eth0.X. In this case, these 2 CTs will be connected to this VLAN.
  • venet device is a bit faster and more efficient.
  • With veth devices, IPv6 auto generates an address from MAC.

The brief summary:

Differences between veth and venet
Feature veth venet
MAC address Yes No
Broadcasts inside CT Yes No
Traffic sniffing Yes No
Network security Low [1] High[2]
Can be used in bridges Yes No
Performance Fast Fastest
  1. Independent of host. Each CT must setup its own separate network security.
  2. Controlled by host.