MIB_IPINTERFACE_ROW structure (netioapi.h)
The MIB_IPINTERFACE_ROW structure stores interface management information for a particular IP address family on a network interface.
Syntax
typedef struct _MIB_IPINTERFACE_ROW {
ADDRESS_FAMILY Family;
NET_LUID InterfaceLuid;
NET_IFINDEX InterfaceIndex;
ULONG MaxReassemblySize;
ULONG64 InterfaceIdentifier;
ULONG MinRouterAdvertisementInterval;
ULONG MaxRouterAdvertisementInterval;
BOOLEAN AdvertisingEnabled;
BOOLEAN ForwardingEnabled;
BOOLEAN WeakHostSend;
BOOLEAN WeakHostReceive;
BOOLEAN UseAutomaticMetric;
BOOLEAN UseNeighborUnreachabilityDetection;
BOOLEAN ManagedAddressConfigurationSupported;
BOOLEAN OtherStatefulConfigurationSupported;
BOOLEAN AdvertiseDefaultRoute;
NL_ROUTER_DISCOVERY_BEHAVIOR RouterDiscoveryBehavior;
ULONG DadTransmits;
ULONG BaseReachableTime;
ULONG RetransmitTime;
ULONG PathMtuDiscoveryTimeout;
NL_LINK_LOCAL_ADDRESS_BEHAVIOR LinkLocalAddressBehavior;
ULONG LinkLocalAddressTimeout;
ULONG ZoneIndices[ScopeLevelCount];
ULONG SitePrefixLength;
ULONG Metric;
ULONG NlMtu;
BOOLEAN Connected;
BOOLEAN SupportsWakeUpPatterns;
BOOLEAN SupportsNeighborDiscovery;
BOOLEAN SupportsRouterDiscovery;
ULONG ReachableTime;
NL_INTERFACE_OFFLOAD_ROD TransmitOffload;
NL_INTERFACE_OFFLOAD_ROD ReceiveOffload;
BOOLEAN DisableDefaultRoutes;
} MIB_IPINTERFACE_ROW, *PMIB_IPINTERFACE_ROW;
Members
Family
Type: ADDRESS_FAMILY
The address family. Possible values for the address family are listed in the Winsock2.h header file. Note that the values for the AF_ address family and PF_ protocol family constants are identical (for example, AF_INET and PF_INET), so either constant can be used.
On Windows Vista and later as well as on the Windows SDK, the organization of header files has changed and possible values for this member are defined in the Ws2def.h header file. Note that the Ws2def.h header file is automatically included in Winsock2.h, and should never be used directly.
The values currently supported are AF_INET or AF_INET6, which are the Internet address family formats for IPv4 and IPv6.
| Value | Meaning |
|---|---|
|
The address family is unspecified. |
|
The Internet Protocol version 4 (IPv4) address family. |
|
The Internet Protocol version 6 (IPv6) address family. |
InterfaceLuid
Type: NET_LUID
The locally unique identifier (LUID) for the network interface.
InterfaceIndex
Type: NET_IFINDEX
The local index value for the network interface. This index value may change when a network adapter is disabled and then enabled, or under other circumstances, and should not be considered persistent.
MaxReassemblySize
Type: ULONG
The maximum reassembly size, in bytes, of a fragmented IP packet. This member is currently set to zero and reserved for future use.
InterfaceIdentifier
Type: ULONG64
Reserved for future use. This member is currently set to zero.
MinRouterAdvertisementInterval
Type: ULONG
The minimum router advertisement interval, in milliseconds, on this IP interface. This member defaults to 200 for IPv6. This member is only applicable if the AdvertisingEnabled member is set to TRUE.
MaxRouterAdvertisementInterval
Type: ULONG
The maximum router advertisement interval, in milliseconds, on this IP interface. This member defaults to 600 for IPv6. This member is only applicable if the AdvertisingEnabled member is set to TRUE.
AdvertisingEnabled
Type: BOOLEAN
A value that indicates if router advertising is enabled on this IP interface. The default for IPv6 is that router advertisement is enabled only if the interface is configured to act as a router. The default for IPv4 is that router advertisement is disabled.
ForwardingEnabled
Type: BOOLEAN
A value that indicates if IP forwarding is enabled on this IP interface.
WeakHostSend
Type: BOOLEAN
A value that indicates if weak host send mode is enabled on this IP interface.
WeakHostReceive
Type: BOOLEAN
A value that indicates if weak host receive mode is enabled on this IP interface.
UseAutomaticMetric
Type: BOOLEAN
A value that indicates if the IP interface uses automatic metric.
UseNeighborUnreachabilityDetection
Type: BOOLEAN
A value that indicates if neighbor unreachability detection is enabled on this IP interface.
ManagedAddressConfigurationSupported
Type: BOOLEAN
A value that indicates if the IP interface supports managed address configuration using DHCP.
OtherStatefulConfigurationSupported
Type: BOOLEAN
A value that indicates if the IP interface supports other stateful configuration (route configuration, for example).
AdvertiseDefaultRoute
Type: BOOLEAN
A value that indicates if the IP interface advertises the default route. This member is only applicable if the AdvertisingEnabled member is set to TRUE.
RouterDiscoveryBehavior
Type: NL_ROUTER_DISCOVERY_BEHAVIOR
The router discovery behavior. This member can be one of the values from the NL_ROUTER_DISCOVERY_BEHAVIOR enumeration type defined in the Nldef.h header file. The member is described in RFC 2461. For more information, see http://www.ietf.org/rfc/rfc2461.txt.
DadTransmits
Type: ULONG
The number of consecutive messages sent while performing duplicate address detection on a tentative IP unicast address. A value of zero indicates that duplicate address detection is not performed on tentative IP addresses. A value of one indicates a single transmission with no follow up retransmissions. For IPv4, the default for this member is 3. For IPv6, the default for this member is 1. For IPv6, these messages will sent as neighbor solicitation requests. This member is defined as DupAddrDetectTransmits in RFC 2462. For more information, see http://www.ietf.org/rfc/rfc2462.txt.
BaseReachableTime
Type: ULONG
The base for random reachable time, in milliseconds. The member is described in RFC 2461. For more information, see http://www.ietf.org/rfc/rfc2461.txt.
RetransmitTime
Type: ULONG
The neighbor solicitation timeout, in milliseconds. The member is described in RFC 2461. For more information, see http://www.ietf.org/rfc/rfc2461.txt.
PathMtuDiscoveryTimeout
Type: ULONG
The path MTU discovery timeout, in milliseconds.
LinkLocalAddressBehavior
Type: NL_LINK_LOCAL_ADDRESS_BEHAVIOR
The link local address behavior. This member can be one of the values from the NL_LINK_LOCAL_ADDRESS_BEHAVIOR enumeration type defined in the Nldef.h header file.
LinkLocalAddressTimeout
Type: ULONG
The link local IP address timeout, in milliseconds.
ZoneIndices[ScopeLevelCount]
Type: ULONG[ScopeLevelCount]
An array that specifies the zone part of scope IDs.
SitePrefixLength
Type: ULONG
The site prefix length, in bits, of the IP interface address. The length, in bits, of the site prefix or network part of the IP interface address. For an IPv4 address, any value greater than 32 is an illegal value. For an IPv6 address, any value greater than 128 is an illegal value. A value of 255 is commonly used to represent an illegal value.
Metric
Type: ULONG
The interface metric. Note the actual route metric used to compute the route preference is the summation of the route metric offset specified in the Metric member of the MIB_IPFORWARD_ROW2 structure and the interface metric specified in this member.
NlMtu
Type: ULONG
The network layer MTU size, in bytes.
Connected
Type: BOOLEAN
A value that indicates if the interface is connected to a network access point.
SupportsWakeUpPatterns
Type: BOOLEAN
A value that specifies if the network interface supports Wake on LAN.
SupportsNeighborDiscovery
Type: BOOLEAN
A value that specifies if the IP interface support neighbor discovery.
SupportsRouterDiscovery
Type: BOOLEAN
A value that specifies if the IP interface support router discovery.
ReachableTime
Type: ULONG
The reachable timeout, in milliseconds.
TransmitOffload
Type: NL_INTERFACE_OFFLOAD_ROD
A set of flags that indicate the transmit offload capabilities for the IP interface. The NL_INTERFACE_OFFLOAD_ROD structure is defined in the Nldef.h header file.
ReceiveOffload
Type: NL_INTERFACE_OFFLOAD_ROD
A set of flags that indicate the receive offload capabilities for the IP interface. The NL_INTERFACE_OFFLOAD_ROD structure is defined in the Nldef.h header file.
DisableDefaultRoutes
Type: BOOLEAN
A value that indicates if using default route on the interface should be disabled. This member can be used by VPN clients to restrict split tunneling.
Remarks
The MIB_IPINTERFACE_ROW structure is defined on Windows Vista and later.
The Family, InterfaceLuid, and InterfaceIndex members uniquely identify a MIB_IPINTERFACE_ROW entry.
When a unicast packet arrives at a host, IP must determine whether the packet is locally destined (its destination matches an address that is assigned to an interface of the host). IP implementations that follow a weak host model accept any locally destined packet, regardless of the interface on which the packet was received. IP implementations that follow the strong host model only accept locally destined packets if the destination address in the packet matches an address assigned to the interface on which the packet was received. The weak host model provides better network connectivity. However, it also makes hosts susceptible to multihome-based network attacks.
The current IPv4 implementation in Windows Server 2003 and Windows XP uses the weak host model. In this case, all unicast packets are sent out the interface with the lowest metric for a route.
The TCP/IP stack on Windows Vista and later supports the strong host model for both IPv4 and IPv6 and is configured to use the strong host mode by default (the WeakHostReceive and WeakHostSend members are set to FALSE). With the strong host mode, a unicast packet can be sent out a specific interface that does not have the lowest metric for a route by binding the socket to the source address of the specific interface.
The TCP/IP stack on Windows Vista and later can be configured to use a weak host model.
A metric is a value that is assigned to an IP route for a particular network interface that identifies the cost that is associated with using that route. For example, the metric can be valued in terms of link speed, hop count, or time delay. Automatic metric is a feature on Windows XP and later that automatically configures the metric for the local routes that are based on link speed. The automatic metric feature is enabled by default (the UseAutomaticMetric is set to TRUE) on Windows XP and later. It can also be manually configured to assign a specific metric to an IP route.
The automatic metric feature can be useful when the routing table contains multiple routes for the same destination. For example, a computer with a 10 megabit network interface and a 100 megabit network interface has a default gateway that is configured on both network interfaces. When UseAutomaticMetric is TRUE, this feature can force all of the traffic that is destined for the Internet, for example, to use the fastest network interface that is available.
The interface metric specified in the Metric member represents just the metric for the interface. The complete routing metric is a combination of this interface metric added to the route metric offset specified in the Metric member of the MIB_IPFORWARD_ROW2 structure of a route entry specified on this interface.
Unprivileged simultaneous access to multiple networks of different security requirements creates a security hole and allows an unprivileged application to accidentally relay data between the two networks. A typical example is simultaneous access to a virtual private network (VPN) and the internet. Windows Server 2003 and Windows XP use a weak host model, where RAS prevents such simultaneous access by increasing the route metric of all default routes over other interfaces. Thus all traffic is routed through the VPN interface, disrupting other network connectivity.
On Windows Vista and later, a strong host model is used by default. If a source IP address is specified in the route lookup using GetBestRoute2 or GetBestRoute, the route lookup is restricted to the interface of the source IP address. The route metric modification by RAS has no effect as the list of potential routes does not even have the route for the VPN interface thereby allowing traffic to the internet. The DisableDefaultRoutes member of the MIB_IPINTERFACE_ROW structure can be used to disable using the default route on an interface. This member can be used as a security measure by VPN clients to restrict split tunneling when split tunneling is not required by the VPN client. A VPN client can call the SetIpInterfaceEntry function to set the DisableDefaultRoutes member to TRUE when required. A VPN client can query the current state of the DisableDefaultRoutes member by calling the GetIpInterfaceEntry function.
Note that the Netioapi.h header file is automatically included in the Iphlpapi.h header file. The Netioapi.h header file should never be used directly.
Examples
To view an example that retrieves the MIB_IPINTERFACE_TABLE structure and then prints out a few members of the MIB_IPINTERFACE_ROW structure entries in this table, see the GetIpInterfaceTable function.
Requirements
| Requirement | Value |
|---|---|
| Minimum supported client | Windows Vista [desktop apps only] |
| Minimum supported server | Windows Server 2008 [desktop apps only] |
| Header | netioapi.h (include Iphlpapi.h) |
See also
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