IPPROTO_IP socket options
The following tables describe IPPROTO_IP socket options that apply to sockets created for the IPv4 address family (AF_INET). See the getsockopt and setsockopt function reference pages for more information on getting and setting socket options.
To enumerate protocols and discover supported properties for each installed protocol, use the WSAEnumProtocols, WSCEnumProtocols, or WSCEnumProtocols32 function.
Some socket options require more explanation than these tables can convey; such options contain links to additional pages.
Options
| Option | Get | Set | Optval type | Description |
|---|---|---|---|---|
| IP_ADD_IFLIST | yes | DWORD (IF_INDEX) | Adds an interface index to the IFLIST associated with the IP_IFLIST option. | |
| IP_ADD_MEMBERSHIP | yes | ip_mreq | Join the socket to the supplied multicast group on the specified interface. | |
| IP_ADD_SOURCE_MEMBERSHIP | yes | ip_mreq_source | Join the supplied multicast group on the given interface and accept data sourced from the supplied source address. | |
| IP_BLOCK_SOURCE | yes | ip_mreq_source | Removes the given source as a sender to the supplied multicast group and interface. | |
| IP_DEL_IFLIST | yes | DWORD (IF_INDEX) | Removes an interface index from the IFLIST associated with the IP_IFLIST option. Entries can be removed only by the application, so be aware that entries might go stale once an interface is removed. | |
| IP_DONTFRAGMENT | yes | yes | DWORD (boolean) | Indicates that data should not be fragmented regardless of the local MTU. Valid only for message oriented protocols. Microsoft TCP/IP providers respect this option for UDP and ICMP. |
| IP_DROP_MEMBERSHIP | yes | ip_mreq | Leaves the specified multicast group from the specified interface. Service providers must support this option when multicast is supported. Support is indicated in the WSAPROTOCOL_INFO structure returned by a WSAEnumProtocols function call with the following: XPI_SUPPORT_MULTIPOINT=1, XP1_MULTIPOINT_CONTROL_PLANE=0, XP1_MULTIPOINT_DATA_PLANE=0. | |
| IP_DROP_SOURCE_MEMBERSHIP | yes | ip_mreq_source | Drops membership to the given multicast group, interface, and source address. | |
| IP_GET_IFLIST | yes | DWORD[] (IF_INDEX[]) | Gets the current IFLIST associated with the IP_IFLIST option. Returns error if IP_IFLIST is not enabled. | |
| IP_HDRINCL | yes | yes | DWORD (boolean) | When set to TRUE, indicates the application provides the IP header. Applies only to SOCK_RAW sockets. The TCP/IP service provider may set the ID field, if the value supplied by the application is zero. The IP_HDRINCL option is applied only to the SOCK_RAW type of protocol. A TCP/IP service provider that supports SOCK_RAW should also support IP_HDRINCL. |
| IP_IFLIST | yes | yes | DWORD (boolean) | Gets or sets the IP_IFLIST state of the socket. When this option is set to true, Datagram reception is restricted to interfaces that are in the IFLIST. Datagrams received on any other interfaces are ignored. IFLIST starts empty. Use IP_ADD_IFLIST and IP_DEL_IFLIST to edit the IFLIST. |
| IP_MTU | yes | DWORD | Gets the system's estimate of the path MTU. Socket must be connected. | |
| IP_MTU_DISCOVER | yes | yes | DWORD (PMTUD_STATE) | Gets or sets the path MTU discovery state for the socket. The default value is IP_PMTUDISC_NOT_SET. For stream sockets, IP_PMTUDISC_NOT_SET and IP_PMTUDISC_DO will perform path MTU discovery. IP_PMTUDISC_DONT and IP_PMTUDISC_PROBE will turn off path MTU discovery. For datagram sockets, IP_PMTUDISC_DO will force all outgoing packets to have the DF bit set and an attempt to send packets larger than path MTU will result in an error. IP_PMTUDISC_DONT will force all outgoing packets to have the DF bit not set, and packets will be fragmented according to interface MTU. IP_PMTUDISC_PROBE will force all outgoing packets to have the DF bit set, and an attempt to send packets larger than interface MTU will result in an error. |
| IP_MULTICAST_IF | yes | yes | DWORD | Gets or sets the outgoing interface for sending IPv4 multicast traffic. This option does not change the default interface for receiving IPv4 multicast traffic. The input value for setting this option is a 4-byte IPv4 address in network byte order. This DWORD parameter can also be an interface index in network byte order. Any IP address in the 0.x.x.x block (first octet of 0) except IPv4 address 0.0.0.0 is treated as an interface index. An interface index is a 24-bit number, and the 0.0.0.0/8 IPv4 address block is not used (this range is reserved). The interface index can be used to specify the default interface for multicast traffic for IPv4. If optval is zero , the default interface for receiving multicast is specified for sending multicast traffic. When getting this option, the optval returns the current default interface index for sending multicast IPv4 traffic in host byte order. |
| IP_MULTICAST_LOOP | yes | yes | DWORD (boolean) | For a socket that is joined to one or more multicast groups, this controls whether it will receive a copy of outgoing packets sent to those multicast groups via the selected multicast interface. By default, IP_MULTICAST_LOOP is enabled (value 1/TRUE), so sockets will receive matching multicast packets sent by the current machine. Disabling this option (by setting it to 0/FALSE) means that this socket will not receive multicasts sent from the local machine, even if the socket is open on the loopback interface. This is not compatible with the POSIX version of IP_MULTICAST_LOOP—the option must be set on the receiving socket; while the POSIX option must be set on the sending socket. |
| IP_MULTICAST_TTL | yes | yes | DWORD | Sets/gets the TTL value associated with IP multicast traffic on the socket. |
| IP_OPTIONS | yes | yes | char [] | Specifies IP options to be inserted into outgoing packets. Setting new options overwrites all previously specified options. Setting optval to zero removes all previously specified options. IP_OPTIONS support is not required; to check whether IP_OPTIONS is supported, use getsockopt to get current options. If getsockopt fails, IP_OPTIONS is not supported. |
| IP_ORIGINAL_ARRIVAL_IF | yes | yes | DWORD (boolean) | Indicates if the LPFN_WSARECVMSG (WSARecvMsg) function should return optional control data containing the arrival interface where the packet was received for datagram sockets. This option allows the IPv4 interface where the packet was received to be returned in the WSAMSG structure. This option is only valid on datagram and raw sockets (the socket type must be SOCK_DGRAM or SOCK_RAW). |
| IP_PKTINFO | yes | yes | DWORD | Indicates that packet information should be returned by the WSARecvMsg function. |
| IP_RECEIVE_BROADCAST | yes | yes | DWORD (boolean) | Allows or blocks broadcast reception. |
| IP_RECVIF | yes | yes | DWORD (boolean) | Indicates whether the IP stack should populate the control buffer with details about which interface received a packet with a datagram socket. When this value is true, the LPFN_WSARECVMSG (WSARecvMsg) function will return optional control data containing the interface where the packet was received for datagram sockets. This option allows the IPv4 interface where the packet was received to be returned in the WSAMSG structure. This option is only valid on datagram and raw sockets (the socket type must be SOCK_DGRAM or SOCK_RAW). |
| IP_RECVTOS | yes | yes | DWORD (boolean) | Indicates whether the IP stack should populate the control buffer with a message containing the Type of Service (TOS) IPv4 header field on a received datagram. When this value is true, the LPFN_WSARECVMSG (WSARecvMsg) function will return optional control data containing the TOS IPv4 header field value of the received datagram. This option allows the TOS IPv4 header field of the received datagram to be returned in the WSAMSG structure. The returned message type will be IP_TOS. All DSCP and ECN bits of the TOS field will be returned. This option is only valid on datagram sockets (the socket type must be SOCK_DGRAM). |
| IP_RECVECN | yes | yes | DWORD (boolean) | Indicates whether the IP stack should populate the control buffer with a message containing the ECN bits of the Type of Service (TOS) IPv4 header field on a received datagram. When this value is true, the LPFN_WSARECVMSG (WSARecvMsg) function will return optional control data containing the ECN bits of the TOS IPv4 header field value of the received datagram. This option allows the ECN bits of the TOS IPv4 header field of the received datagram to be returned in the WSAMSG structure. The returned message type will be IP_ECN. All 2 ECN bits of the TOS field will be returned. This option is only valid on datagram and raw sockets (the socket type must be SOCK_DGRAM or SOCK_RAW). For type-safety, you should use the WSAGetRecvIPEcn and WSASetRecvIPEcn functions instead of using the socket option directly. |
| IP_RECVTTL | yes | yes | DWORD (boolean) | Indicates that hop (TTL) information should be returned in the LPFN_WSARECVMSG (WSARecvMsg) function. If optval is set to 1 on the call to setsockopt, the option is enabled. If set to 0, the option is disabled. This option is only valid for datagram and raw sockets (the socket type must be SOCK_DGRAM or SOCK_RAW). |
| IP_TOS | yes | yes | DWORD (boolean) | Do not use. Type of Service (TOS) settings should only be set using the Quality of Service API. See Differentiated Services in the Quality of Service section of the Platform SDK for more information. |
| IP_TTL | yes | yes | DWORD (boolean) | Changes the default value set by the TCP/IP service provider in the TTL field of the IP header in outgoing datagrams. IP_TTL support is not required; to check whether IP_TTL is supported, use getsockopt to get current options. If getsockopt fails, IP_TTL is not supported. |
| IP_UNBLOCK_SOURCE | yes | ip_mreq_source | Adds the given source as a sender to the supplied multicast group and interface. | |
| IP_UNICAST_IF | yes | yes | DWORD (IF_INDEX) | Gets or sets the outgoing interface for sending IPv4 traffic. This option does not change the default interface for receiving IPv4 traffic. This option is important for multihomed computers. The input value for setting this option is a 4-byte IPv4 address in network byte order. This DWORD parameter must be an interface index in network byte order. Any IP address in the 0.x.x.x block (first octet of 0) except IPv4 address 0.0.0.0 is treated as an interface index. An interface index is a 24-bit number, and the 0.0.0.0/8 IPv4 address block is not used (this range is reserved). The interface index can be used to specify the default interface for sending traffic for IPv4. The GetAdaptersAddresses function can be used to obtain the interface index information. If optval is zero , the default interface for sending traffic is set to unspecified. When getting this option, the optval returns the current default interface index for sending IPv4 traffic in host byte order. |
| IP_USER_MTU | yes | yes | DWORD | Gets or sets an upper bound on the IP layer MTU (in bytes) for the given socket. If the value is higher than the system's estimate of the path MTU (which you can retrieve on a connected socket by querying the IP_MTU socket option), then the option has no effect. If the value is lower, then outbound packets larger than this will be fragmented, or will fail to send, depending on the value of IP_DONTFRAGMENT. Default value is IP_UNSPECIFIED_USER_MTU (MAXULONG). For type-safety, you should use the WSAGetIPUserMtu and WSASetIPUserMtu functions instead of using the socket option directly. |
| IP_WFP_REDIRECT_CONTEXT | yes | yes | WSACMSGHDR with control data | A datagram socket ancillary data type (cmsg_type) to indicate the redirect context for a UDP socket used by a user mode Windows Filtering Platform (WFP) redirect service. |
| IP_WFP_REDIRECT_RECORDS | yes | yes | WSACMSGHDR with control data | A datagram socket ancillary data type (cmsg_type) to indicate the redirect record for a UDP socket used by a user mode Windows Filtering Platform (WFP) redirect service. |
Windows support for IP_PROTO options
| Option | Windows 10 | Windows 8 | Windows Server 2012 | Windows 7 | Windows Server 2008 | Windows Vista |
|---|---|---|---|---|---|---|
| IP_ADD_IFLIST | Starting with Windows 10, version 1803 | |||||
| IP_ADD_MEMBERSHIP | yes | yes | yes | yes | yes | yes |
| IP_ADD_SOURCE_MEMBERSHIP | yes | yes | yes | yes | yes | yes |
| IP_BLOCK_SOURCE | yes | yes | yes | yes | yes | yes |
| IP_DEL_IFLIST | Starting with Windows 10, version 1803 | |||||
| IP_DONTFRAGMENT | yes | yes | yes | yes | yes | yes |
| IP_DROP_MEMBERSHIP | yes | yes | yes | yes | yes | yes |
| IP_DROP_SOURCE_MEMBERSHIP | yes | yes | yes | yes | yes | yes |
| IP_GET_IFLIST | Starting with Windows 10, version 1803 | |||||
| IP_HDRINCL | yes | yes | yes | yes | yes | yes |
| IP_IFLIST | Starting with Windows 10, version 1803 | |||||
| IP_MULTICAST_IF | yes | yes | yes | yes | yes | yes |
| IP_MULTICAST_LOOP | yes | yes | yes | yes | yes | yes |
| IP_MULTICAST_TTL | yes | yes | yes | yes | yes | yes |
| IP_OPTIONS | yes | yes | yes | yes | yes | yes |
| IP_ORIGINAL_ARRIVAL_IF | yes | yes | yes | yes | ||
| IP_PKTINFO | yes | yes | yes | yes | yes | yes |
| IP_RECEIVE_BROADCAST | yes | yes | yes | yes | yes | yes |
| IP_RECVIF | Starting with Windows 10, version 1703 | yes | yes | yes | yes | yes |
| IP_RECVTTL | yes | |||||
| IP_TOS | yes | yes | yes | |||
| IP_TTL | yes | yes | yes | yes | yes | yes |
| IP_UNBLOCK_SOURCE | yes | yes | yes | yes | yes | yes |
| IP_UNICAST_IF | yes | yes | yes | yes | yes | yes |
| IP_WFP_REDIRECT_CONTEXT | yes | yes | yes | |||
| IP_WFP_REDIRECT_RECORDS | yes | yes | yes |
| Option | Windows Server 2003 | Windows XP |
|---|---|---|
| IP_ADD_IFLIST | ||
| IP_ADD_MEMBERSHIP | yes | yes |
| IP_ADD_SOURCE_MEMBERSHIP | yes | yes |
| IP_BLOCK_SOURCE | yes | yes |
| IP_DEL_IFLIST | ||
| IP_DONTFRAGMENT | yes | yes |
| IP_DROP_MEMBERSHIP | yes | yes |
| IP_DROP_SOURCE_MEMBERSHIP | yes | yes |
| IP_GET_IFLIST | ||
| IP_HDRINCL | yes | yes |
| IP_IFLIST | ||
| IP_MULTICAST_IF | yes | yes |
| IP_MULTICAST_LOOP | yes | yes |
| IP_MULTICAST_TTL | yes | yes |
| IP_OPTIONS | yes | yes |
| IP_ORIGINAL_ARRIVAL_IF | ||
| IP_PKTINFO | yes | yes |
| IP_RECEIVE_BROADCAST | yes | yes |
| IP_RECVIF | ||
| IP_RECVTTL | ||
| IP_TOS | ||
| IP_TTL | yes | yes |
| IP_UNBLOCK_SOURCE | yes | yes |
| IP_UNICAST_IF | ||
| IP_WFP_REDIRECT_CONTEXT | ||
| IP_WFP_REDIRECT_RECORDS |
Remarks
In the Microsoft Windows Software Development Kit (SDK) released for Windows Vista and later, the organization of header files has changed and IPPROTO_IP level is defined in the Ws2def.h header file which is automatically included in the Winsock2.h header file. Some of the IPPROTO_IP socket options are defined in the Ws2ipdef.h header file which is automatically included by the Ws2tcpip.h header file. The remaining IPPROTO_IP socket options are defined in the Wsipv6ok.h header file which is automatically included by the Winsock2.h header file. The Ws2def.h, Ws2ipdef.h, and Wsipv6ok.h header files should never be used directly.
In the Platform SDK released for Windows Server 2003 and Windows XP, the IPPROTO_IP level is defined in the Winsock2.h header file. Some of the IPPROTO_IP socket options are defined in the Ws2tcpip.h header file. The remaining IPPROTO_IP socket options are defined in the Wsipv6ok.h header file which is automatically included by the Winsock2.h header file. The Wsipv6ok.h header file should never be used directly.
Requirements
| Requirement | Value |
|---|---|
| Header |
|