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)