---
name: "ng_iface"
section: "4"
platform: "linux"
package: "freebsd-manpages"
version: "6.0-5"
release: "Debian 4.0 (Etch)"
platforms: ["linux", "freebsd"]
url: "https://new.carta.tech/ng_iface"
---

# ng\_iface(4)

interface netgraph node type

## NAME

**ng\_iface** – interface netgraph node type

## SYNOPSIS

**#include \<netgraph/ng\_iface.h\>**

## DESCRIPTION

An **iface** node is both a netgraph node and a system networking interface. When an **iface** node is created, a new interface appears which is accessible via [ifconfig(8)](/ifconfig/8.md). **Iface** node interfaces are named ng0, ng1, etc. When a node is shutdown, the corresponding interface is removed and the interface name becomes available for reuse by future **iface** nodes; new nodes always take the first unused interface. The node itself is assigned the same name as its interface, unless the name already exists, in which case the node remains unnamed.

An **iface** node has a single hook corresponding to each supported protocol. Packets transmitted via the interface flow out the corresponding protocol-specific hook. Similarly, packets received on a hook appear on the interface as packets received into the corresponding protocol stack. The currently supported protocols are IP, IPv6, AppleTalk, IPX, ATM, NATM, and NS.

An **iface** node can be configured as a point-to-point interface or a broadcast interface. The configuration can only be changed when the interface is down. The default mode is point-to-point.

**Iface** nodes support the Berkeley Packet Filter (BPF).

## HOOKS

This node type supports the following hooks:

- inet

  Transmission and reception of IP packets.

- inet6

  Transmission and reception of IPv6 packets.

- atalk

  Transmission and reception of AppleTalk packets.

- ipx

  Transmission and reception of IPX packets.

- atm

  Transmission and reception of ATM packets.

- natm

  Transmission and reception of NATM packets.

- ns

  Transmission and reception of NS packets.

## CONTROL MESSAGES

This node type supports the generic control messages, plus the following:

- NGM\_IFACE\_GET\_IFNAME

  Returns the name of the associated interface as a NUL-terminated ASCII string. Normally this is the same as the name of the node.

- NGM\_IFACE\_POINT2POINT

  Set the interface to point-to-point mode. The interface must not currently be up.

- NGM\_IFACE\_BROADCAST

  Set the interface to broadcast mode. The interface must not currently be up.

- NGM\_CISCO\_GET\_IPADDR

  This message is defined by the [ng\_cisco(4)](/ng_cisco/4.md) node type; see [ng\_cisco(4)](/ng_cisco/4.md) for a description.

## SHUTDOWN

This node shuts down upon receipt of a NGM\_SHUTDOWN control message. The associated interface is removed and becomes available for use by future **iface** nodes.

Unlike most other node types, an **iface** node does *not* go away when all hooks have been disconnected; rather, and explicit NGM\_SHUTDOWN control message is required.

## SEE ALSO

[bpf(4)](/bpf/4.md), [netgraph(4)](/netgraph/4.md), [ng\_cisco(4)](/ng_cisco/4.md), [ifconfig(8)](/ifconfig/8.md), [ngctl(8)](/ngctl/8.md)

## HISTORY

The **iface** node type was implemented in FreeBSD 4.0.

## AUTHORS

Archie Cobbs ⟨archie@FreeBSD.org⟩