.\" $OpenBSD: vxlan.4,v 1.3 2013/10/13 10:52:35 jmc Exp $ .\" .\" Copyright (c) 2013 Reyk Floeter .\" .\" Permission to use, copy, modify, and distribute this software for any .\" purpose with or without fee is hereby granted, provided that the above .\" copyright notice and this permission notice appear in all copies. .\" .\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES .\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF .\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR .\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES .\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN .\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF .\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. .\" .Dd $Mdocdate: October 13 2013 $ .Dt VXLAN 4 .Os .Sh NAME .Nm vxlan .Nd virtual extensible local area network tunnel interface .Sh SYNOPSIS .Cd "pseudo-device vxlan" .Sh DESCRIPTION The .Nm interface is a tunnelling pseudo-device for overlaying virtualized layer 2 networks over layer 3 networks. .Pp A .Nm interface can be created using the .Ic ifconfig vxlan Ns Ar N Ic create command. Once configured, the interface encapsulates and decapsulates Ethernet frames in UDP datagrams that are exchanged with tunnel endpoints. The default UDP port for VXLAN traffic is 4789. .Pp Each .Nm interface uses a 24-bit .Ic vnetid (virtual networks identifier) that distinguishes multiple virtualized layer 2 networks and their tunnels between identical tunnel endpoints. .Pp The interface can operate in three different tunnel modes: .Bl -tag -width multicast .It Ic unicast mode When a unicast IP address is configured as the tunnel destination, all traffic is sent to a single tunnel endpoint. .It Ic multicast mode When a multicast IP address is configured as the tunnel destination, all traffic is sent to all the tunnel endpoints that subscribed for the specified multicast group. .It Ic dynamic mode When .Nm is configured for multicast mode and added to a .Xr bridge 4 , all broadcast and multicast traffic is sent to the multicast group, but directed traffic is sent to unicast IP addresses of individual tunnel endpoints, as they are learned by the bridge. .El .Pp The configuration can be done at runtime or by setting up a .Xr hostname.if 5 configuration file for .Xr netstart 8 . .Sh EXAMPLES Create a tunnel to a unicast tunnel endpoint, using the virtual tunnel identifier 5: .Bd -literal -offset indent # ifconfig vxlan0 tunnel 192.168.1.100 192.168.1.200 vnetid 5 # ifconfig vxlan0 10.1.1.100/24 .Ed .Pp The following examples creates a dynamic tunnel that is attached to a .Xr bridge 4 : .Bd -literal -offset indent # ifconfig vxlan0 tunnel 192.168.1.100 239.1.1.100 vnetid 7395 # ifconfig vxlan0 10.1.2.100/24 # ifconfig bridge0 add vxlan0 up .Ed .Pp Prior to the assignment of UDP port 4789 by IANA, some early VXLAN implementations used port 8472. A non-standard port can be specified with the tunnel destination address: .Bd -literal -offset indent # ifconfig vxlan0 tunnel 192.168.1.100 239.1.1.100:8472 .Ed .Sh SECURITY .Nm does not provide any integrated security features. It is designed to be a simple protocol that can be used in trusted data center environments, to carry VM traffic between virtual machine hypervisors, and provide virtualized layer 2 networks in Cloud infrastructures. .Pp To protect .Nm tunnels, the traffic can be protected with IPsec to add authentication and encryption for confidentiality. .Pp The Packet Filter (PF) can be used to filter tunnel traffic with endpoint policies in .Xr pf.conf 5 : .Bd -literal -offset indent table { 192.168.1.200 192.168.1.201 } block in on vmx0 pass out on vmx0 pass in on vmx0 proto udp from to port 4789 .Ed .Pp The Time-to-Live (TTL) value of the tunnel can be set to 1 or a low value to restrict the traffic to the local network: .Bd -literal -offset indent # ifconfig vxlan0 tunnelttl 1 .Ed .Sh SEE ALSO .Xr bridge 4 , .Xr inet 4 , .Xr hostname.if 5 , .Xr ifconfig 8 , .Xr netstart 8 .Sh STANDARDS .Rs .%A M. Mahalingam .%A D. Dutt .%A K. Duda .%A P. Agarwal .%A L. Kreeger .%A T. Sridhar .%A M. Bursell .%A C. Wright .%D May 2013 .%R draft-mahalingam-dutt-dcops-vxlan-04 .%T VXLAN: A Framework for Overlaying Virtualized Layer 2 Networks over Layer 3 Networks .Re .Sh HISTORY The .Nm device first appeared in .Ox 5.5 . .Sh AUTHORS The .Nm driver was written by .An Reyk Floeter Aq Mt reyk@openbsd.org . .Sh CAVEATS The .Nm interface requires at least 50 bytes for the IP, UDP and VXLAN protocol overhead and optionally 4 bytes for the encapsulated VLAN tag. The default MTU is set to 1500 bytes but can be adjusted if the transport interfaces carrying the tunnel traffic do not support larger MTUs, the tunnel traffic is leaving the local network, or if interoperability with another implementation requires running a decreased MTU of 1450 bytes. In any other case, it is commonly recommended to set the MTU of the transport interfaces to at least 1600 bytes. .Pp The implementation does not support IPv6 tunnel endpoints at present.