{ "mode": "man", "parameter": "address_families", "section": "7", "url": "https://www.chedong.com/phpMan.php/man/address_families/7/json", "generated": "2026-06-03T02:35:48Z", "synopsis": "#include /* See NOTES */", "sections": { "NAME": { "content": "addressfamilies - socket address families (domains)\n", "subsections": [] }, "SYNOPSIS": { "content": "#include /* See NOTES */", "subsections": [ { "name": "#include ", "content": "int socket(int domain, int type, int protocol);\n" } ] }, "DESCRIPTION": { "content": "The domain argument of the socket(2) specifies a communication domain; this selects the pro‐\ntocol family which will be used for communication. These families are defined in\n. The formats currently understood by the Linux kernel include:\n\nAFUNIX, AFLOCAL\nLocal communication For further information, see unix(7).\n\nAFINET\nIPv4 Internet protocols. For further information, see ip(7).\n\nAFAX25\nAmateur radio AX.25 protocol. For further information, see ax25(4).\n\nAFIPX IPX - Novell protocols.\n\nAFAPPLETALK\nAppleTalk For further information, see ddp(7).\n\nAFNETROM\nAX.25 packet layer protocol. For further information, see netrom(4), The Packet Radio\nProtocols and Linux ⟨https://www.tldp.org/HOWTO/AX25-HOWTO/x61.html⟩ and the AX.25,\nNET/ROM, and ROSE network programming chapters of the Linux Amateur Radio AX.25 HOWTO\n⟨https://www.tldp.org/HOWTO/AX25-HOWTO/x2107.html⟩.\n\nAFBRIDGE\nCan't be used for creating sockets; mostly used for bridge links in rtnetlink(7) pro‐\ntocol commands.\n\nAFATMPVC\nAccess to raw ATM Permanent Virtual Circuits (PVCs). For further information, see the\nATM on Linux HOWTO ⟨https://www.tldp.org/HOWTO/text/ATM-Linux-HOWTO⟩.\n\nAFX25 ITU-T X.25 / ISO-8208 protocol. For further information, see x25(7).\n\nAFINET6\nIPv6 Internet protocols. For further information, see ipv6(7).\n\nAFROSE\nRATS (Radio Amateur Telecommunications Society) Open Systems environment (ROSE) AX.25\npacket layer protocol. For further information, see the resources listed for\nAFNETROM.\n\nAFDECnet\nDECet protocol sockets. See Documentation/networking/decnet.txt in the Linux kernel\nsource tree for details.\n\nAFNETBEUI\nReserved for \"802.2LLC project\"; never used.\n\nAFSECURITY\nThis was a short-lived (between Linux 2.1.30 and 2.1.99pre2) protocol family for fire‐\nwall upcalls.\n\nAFKEY Key management protocol, originally developed for usage with IPsec (since Linux\n2.1.38). This has no relation to keyctl(2) and the in-kernel key storage facility.\nSee RFC 2367 PFKEY Key Management API, Version 2\n⟨https://tools.ietf.org/html/rfc2367⟩ for details.\n\nAFNETLINK\nKernel user interface device For further information, see netlink(7).\n\nAFPACKET\nLow-level packet interface. For further information, see packet(7).\n\nAFECONET\nAcorn Econet protocol (removed in Linux 3.5). See the Econet documentation\n⟨http://www.8bs.com/othrdnld/manuals/econet.shtml⟩ for details.\n\nAFATMSVC\nAccess to ATM Switched Virtual Circuits (SVCs) See the ATM on Linux HOWTO\n⟨https://www.tldp.org/HOWTO/text/ATM-Linux-HOWTO⟩ for details.\n\nAFRDS Reliable Datagram Sockets (RDS) protocol (since Linux 2.6.30). RDS over RDMA has no\nrelation to AFSMC or AFXDP. For further information see rds(7), rds-rdma(7), and\nDocumentation/networking/rds.txt in the Linux kernel source tree.\n\nAFIRDA\nSocket interface over IrDA (moved to staging in Linux 4.14, removed in Linux 4.17).\nFor further information see irda(7).\n\nAFPPPOX\nGeneric PPP transport layer, for setting up L2 tunnels (L2TP and PPPoE). See Documen‐\ntation/networking/l2tp.txt in the Linux kernel source tree for details.\n\nAFWANPIPE\nLegacy protocol for wide area network (WAN) connectivity that was used by Sangoma WAN\ncards (called \"WANPIPE\"); removed in Linux 2.6.21.\n\nAFLLC Logical link control (IEEE 802.2 LLC) protocol, upper part of data link layer of\nISO/OSI networking protocol stack (since Linux 2.4); has no relation to AFPACKET.\nSee chapter 13.5.3. Logical Link Control in Understanding Linux Kernel Internals\n(O'Reilly Media, 2006) and IEEE Standards for Local Area Networks: Logical Link Con‐\ntrol (The Institute of Electronics and Electronics Engineers, Inc., New York, New\nYork, 1985) for details. See also some historical notes\n⟨https://wiki.linuxfoundation.org/networking/llc⟩ regarding its development.\n\nAFIB InfiniBand native addressing (since Linux 3.11).\n\nAFMPLS\nMultiprotocol Label Switching (since Linux 4.1); mostly used for configuring MPLS\nrouting via netlink(7), as it doesn't expose ability to create sockets to user space.\n\nAFCAN Controller Area Network automotive bus protocol (since Linux 2.6.25). See Documenta‐\ntion/networking/can.rst in the Linux kernel source tree for details.\n\nAFTIPC\nTIPC, \"cluster domain sockets\" protocol (since Linux 2.6.16). See TIPC Programmer's\nGuide ⟨http://tipc.io/programming.html⟩ and the protocol description\n⟨http://tipc.io/protocol.html⟩ for details.\n\nAFBLUETOOTH\nBluetooth low-level socket protocol (since Linux 3.11). See Bluetooth Management API\noverview ⟨https://git.kernel.org/pub/scm/bluetooth/bluez.git/tree/doc/mgmt-api.txt⟩\nand An Introduction to Bluetooth Programming by Albert Huang\n⟨https://people.csail.mit.edu/albert/bluez-intro/⟩ for details.\n\nAFIUCV\nIUCV (inter-user communication vehicle) z/VM protocol for hypervisor-guest interaction\n(since Linux 2.6.21); has no relation to AFVSOCK and/or AFSMC See IUCV protocol\noverview ⟨https://www.ibm.com/support/knowledgecenter/en/SSB27U6.4.0\n/com.ibm.zvm.v640.hcpb4/iucv.htm⟩ for details.\n\nAFRXRPC\nRx, Andrew File System remote procedure call protocol (since Linux 2.6.22). See Docu‐\nmentation/networking/rxrpc.txt in the Linux kernel source tree for details.\n\nAFISDN\nNew \"modular ISDN\" driver interface protocol (since Linux 2.6.27). See the mISDN wiki\n⟨http://www.misdn.eu/wiki/MainPage/⟩ for details.\n\nAFPHONET\nNokia cellular modem IPC/RPC interface (since Linux 2.6.31). See Documentation/net‐\nworking/phonet.txt in the Linux kernel source tree for details.\n\nAFIEEE802154\nIEEE 802.15.4 WPAN (wireless personal area network) raw packet protocol (since Linux\n2.6.31). See Documentation/networking/ieee802154.txt in the Linux kernel source tree\nfor details.\n\nAFCAIF\nEricsson's Communication CPU to Application CPU interface (CAIF) protocol (since Linux\n2.6.36). See Documentation/networking/caif/Linux-CAIF.txt in the Linux kernel source\ntree for details.\n\nAFALG Interface to kernel crypto API (since Linux 2.6.38). See Documenta‐\ntion/crypto/userspace-if.rst in the Linux kernel source tree for details.\n\nAFVSOCK\nVMWare VSockets protocol for hypervisor-guest interaction (since Linux 3.9); has no\nrelation to AFIUCV and AFSMC. For further information, see vsock(7).\n\nAFKCM KCM (kernel connection multiplexer) interface (since Linux 4.6). See Documenta‐\ntion/networking/kcm.txt in the Linux kernel source tree for details.\n\nAFQIPCRTR\nQualcomm IPC router interface protocol (since Linux 4.7).\n\nAFSMC SMC-R (shared memory communications over RDMA) protocol (since Linux 4.11), and SMC-D\n(shared memory communications, direct memory access) protocol for intra-node z/VM\nquest interaction (since Linux 4.19); has no relation to AFRDS, AFIUCV or AFVSOCK.\nSee RFC 7609 IBM's Shared Memory Communications over RDMA (SMC-R) Protocol\n⟨https://tools.ietf.org/html/rfc7609⟩ for details regarding SMC-R. See SMC-D\nReference Information ⟨https://www-01.ibm.com/software/network/commserver/SMC-\nD/index.html⟩ for details regarding SMC-D.\n\nAFXDP XDP (express data path) interface (since Linux 4.18). See Documentation/network‐\ning/afxdp.rst in the Linux kernel source tree for details.\n", "subsections": [] }, "SEE ALSO": { "content": "socket(2), socket(7)\n", "subsections": [] }, "COLOPHON": { "content": "This page is part of release 5.10 of the Linux man-pages project. A description of the\nproject, information about reporting bugs, and the latest version of this page, can be found\nat https://www.kernel.org/doc/man-pages/.\n\n\n\nLinux 2018-10-16 ADDRESSFAMILIES(7)", "subsections": [] } }, "summary": "addressfamilies - socket address families (domains)", "flags": [], "examples": [], "see_also": [ { "name": "socket", "section": "2", "url": "https://www.chedong.com/phpMan.php/man/socket/2/json" }, { "name": "socket", "section": "7", "url": "https://www.chedong.com/phpMan.php/man/socket/7/json" } ] }