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MIB_IPNET_ROW2 (Compact 2013)

  • Article

3/26/2014

This structure stores information about a neighbor IP address.

Syntax

typedef struct _MIB_IPNET_ROW2 {
  SOCKADDR_INET Address;
  NET_IFINDEX InterfaceIndex;
  NET_LUID InterfaceLuid;
  UCHAR PhysicalAddress[IF_MAX_PHYS_ADDRESS_LENGTH];
  ULONG PhysicalAddressLength;
  NL_NEIGHBOR_STATE State;
  union {
    struct {
      BOOLEAN IsRouter  :1;
      BOOLEAN IsUnreachable  :1;
    };
    UCHAR Flags;
  };
  union {
    ULONG LastReachable;
    ULONG LastUnreachable;
  } ReachabilityTime;
} MIB_IPNET_ROW2, *PMIB_IPNET_ROW2;

Members

  • Address
    The neighbor IP address. This member can be an IPv6 address or an IPv4 address.
  • InterfaceIndex
    The local index value for the network interface associated with this IP address. This index value may change when a network adapter is disabled and then enabled, or under other circumstances, and should not be considered persistent.
  • InterfaceLuid
    The locally unique identifier (LUID) for the network interface associated with this IP address.
  • PhysicalAddress
    The physical hardware address of the adapter for the network interface associated with this IP address.
  • PhysicalAddressLength
    The length, in bytes, of the physical hardware address specified by the PhysicalAddress member. The maximum value supported is 32 bytes.

  • State
    The state of a network neighbor IP address as defined in RFC 2461, section 7.3.2. This member can be one of the values from the NL_NEIGHBOR_STATE enumeration type that is defined in the Nldef.h header file:

    Value

    Meaning

    NlnsUnreachable

    The IP address is unreachable.

    NlnsIncomplete

    Address resolution is in progress and the link-layer address of the neighbor has not yet been determined. Specifically for IPv6, a Neighbor Solicitation has been sent to the solicited-node multicast IP address of the target. However, the corresponding neighbor advertisement has not yet been received.

    NlnsProbe

    The neighbor is no longer known to be reachable, and probes are being sent to verify reachability. For IPv6, a reachability confirmation is actively being sought by retransmitting unicast Neighbor Solicitation probes regularly until a reachability confirmation is received.

    NlnsDelay

    The neighbor is no longer known to be reachable, and traffic has recently been sent to the neighbor. Instead of probing the neighbor immediately, however, delay sending probes for for a while in order to give upper layer protocols an opportunity to provide reachability confirmation. For IPv6, more time has elapsed than is specified in the ReachabilityTime.ReachableTime member since the last positive confirmation was received that the forward path was functioning suitably and a packet was sent. If no reachability confirmation is received in a period of time (used to delay the first probe) of entering the NlnsDelay state, a neighbor solicitation is sent and the State member is changed to NlnsProbe.

    NlnsStale

    The neighbor is no longer known to be reachable but until traffic is sent to the neighbor, no attempt should be made to verify its reachability. For IPv6, more time has elapsed than is specified in the ReachabilityTime.ReachableTime member since the last positive confirmation was received that the forward path was functioning suitably. As long as the State is NlnsStale, no action occurs until a packet is sent. The NlnsStale state is entered upon receiving an unsolicited neighbor discovery message that updates the cached IP address. Receipt of such a message does not confirm reachability, and entering the NlnsStale state insures reachability is verified quickly if the entry is actually being used. However, reachability is not actually verified until the entry is actually used.

    NlnsReachable

    The neighbor is known to have been reachable recently (within tens of seconds ago). For IPv6, a positive confirmation was received within the time specified in the ReachabilityTime.ReachableTime member that the forward path of the neighbor was functioning suitably. As long as the State is NlnsReachable, no special action occurs as packets are sent.

    NlnsPermanent

    The IP address is a permanent address.

    NlnsMaximum

    The maximum possible value for the NL_NEIGHBOR_STATE enumeration type. This is not a legal value for the State member.
  • IsRouter
    A value that indicates if this IP address is a router.
  • IsUnreachable
    A value that indicates if this IP address is unreachable.
  • Flags
    A set of flags that indicate whether the IP address is a router and whether the IP address is unreachable.

  • ReachabilityTime

    • LastReachable
      The time, in milliseconds, that a node assumes a neighbor is reachable after having received a reachability confirmation.
    • LastUnreachable
      The time, in milliseconds, that a node assumes a neighbor is unreachable after not having received a reachability confirmation.

Remarks

The GetIpNetTable2 function enumerates the neighbor IP addresses on a local system and returns this information in a MIB_IPNET_TABLE2 structure. For IPv4, this includes addresses that are determined by using the Address Resolution Protocol (ARP). For IPv6, this includes addresses that are determined by using the Neighbor Discovery (ND) protocol for IPv6 as specified in RFC 2461.

The GetIpNetEntry2 function retrieves a single neighbor IP address and returns this information in a MIB_IPNET_ROW2 structure.

Note

Be aware that the Netioapi.h header file that defines the MIB_IPNET_ROW2 structure is automatically included in the Iphlpapi.h header file. The Netioapi.h header file should never be used directly.

Requirements

Header

iphlpapi.h

See Also

Reference

MIB Structures
CreateIpNetEntry2
GetIpNetEntry2
GetIpNetTable2
MIB_IPNET_TABLE2
SOCKADDR_INET