VNI(4D) Devices VNI(4D)

NAME

vni - STREAMS virtual network interface driver

DESCRIPTION

The vni pseudo device is a multi-threaded, loadable, clonable,
STREAMS pseudo-device supporting the connectionless Data Link
Provider Interface dlpi(4P) Style 2. Note that DLPI is intended to
interact with IP, meaning that DLPI access to applications is not
supported. (For example, snoop fails on the vni interface.)


The vni device is a software-only interface and does not send or
receive data. The device provides a DLPI upper interface that
identifies itself to IP with a private media type. It can be
configured via ifconfig(8) and can have IP addresses assigned to it,
making aliases possible.


The vni pseudo device is particularly useful in hosting an IP address
when used in conjunction with the 'usesrc' ifconfig option (see
ifconfig(8) for examples). The logical instances of the device can
also be used to host addresses as an alternative to hosting them over
the loopback interface.


Multicast is not supported on this device. More specifically, the
following options return an error when used with an address specified
on vni: IP_MULTICAST_IF, IP_ADD_MEMBERSHIP, IP_DROP_MEMBERSHIP,
IPV6_MULTICAST_IF, IPV6_JOIN_GROUP, IPV6_LEAVE_GROUP. In addition,
broadcast is not supported.


Because there is no physical hardware configured below it, no traffic
can be received through nor transmitted on a virtual interface. All
packet transmission and reception is accomplished with existing
physical interfaces and tunnels. Because applications that deal with
packet transmission and reception (such as packet filters) cannot
filter traffic on virtual interfaces, you cannot set up a packet
filter on a virtual interface. Instead, you should configure the
policy rules to apply to the physical interfaces and tunnels, and if
necessary, use the virtual IP addresses themselves as part of the
rule configuration. Also, note that the virtual interface cannot be
part of an IP multipathing (IPMP) group.

FILES

/dev/vni
64-bit ELF kernel driver

SEE ALSO

ip(4P), ip6(4P), ifconfig(8), in.mpathd(8)

July 18, 2004 VNI(4D)