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Internet Gateway Device (UPnP IGD) Control Protocol is a protocol based on UPnP for mapping ports in network address translation (NAT) setups, supported by some NAT-enabled routers. It is a common communications protocol for automatically configuring port forwarding, and is part of an ISO/IEC Standard [1] [2] [3] [4] [5] [6] [7] rather than an Internet Engineering Task Force standard.
Applications using peer-to-peer networks, multiplayer gaming, and remote assistance programs need a way to communicate through home and business gateways. Without IGD one has to manually configure the gateway to allow traffic through, a process which is error-prone and time-consuming. UPnP comes with a solution for network address translation traversal (NAT traversal) that implements IGD.
IGD makes it easy to do the following:
UPnP IGDv2, published in 2010, added IPv6 support and corrected the misconception of an infinite lease time with a value of 0. The specifications are backward compatible, but there are compatibility issues e.g. with the Microsoft client.
There are numerous compatibility issues due the different interpretations of the very large actually backward compatible IGDv1 and IGDv2 specifications. One of them is the UPnP IGD client integrated with current Microsoft Windows and Xbox systems with certified IGDv2 routers. The compatibility issue still exist since the introduced of the IGDv1 client in Windows XP in 2001, and a IGDv2 router without a workaround that makes router port mapping impossible. [8]
If UPnP is only used to control router port mappings and pinholes, there are alternative, newer much simpler and lightweight protocols such as the PCP and the NAT-PMP, both of which have been standardized as RFCs by the IETF. These alternatives are not yet known to have compatibility issues between different clients and servers, but adoption is still low. For consumer routers, only AVM and the open source router software projects OpenWrt, OPNsense, and pfSense are currently known to support PCP as an alternative to UPnP. AVM's Fritz!Box UPnP IGDv2 and PCP implementation has been very buggy since its introduction. In many cases it does not work. [9] [10] [11] [12] [13]
Malware can exploit the IGD protocol to bring connected devices under the control of a foreign user. [14] [15] The Conficker worm is an example of a botnet created using this vector. [14]
The host can discover available IGDv1/IGDv2 devices with only one M-SEARCH for IGDv1 on the network via Simple Service Discovery Protocol (SSDP) which can be controlled then with the help of a network protocol such as SOAP. A discover request is sent via HTTP and port 1900 to the IPv4 multicast address 239.255.255.250 (for the IPv6 addresses see the Simple Service Discovery Protocol (SSDP)):
M-SEARCH * HTTP/1.1 HOST: 239.255.255.250:1900 MAN: "ssdp:discover" MX: 2 ST: urn:schemas-upnp-org:device:InternetGatewayDevice:1
Network address translation (NAT) is a method of mapping an IP address space into another by modifying network address information in the IP header of packets while they are in transit across a traffic routing device. The technique was originally used to bypass the need to assign a new address to every host when a network was moved, or when the upstream Internet service provider was replaced, but could not route the network's address space. It has become a popular and essential tool in conserving global address space in the face of IPv4 address exhaustion. One Internet-routable IP address of a NAT gateway can be used for an entire private network.
Universal Plug and Play (UPnP) is a set of networking protocols on the Internet Protocol (IP) that permits networked devices, such as personal computers, printers, Internet gateways, Wi-Fi access points and mobile devices, to seamlessly discover each other's presence on the network and establish functional network services. UPnP is intended primarily for residential networks without enterprise-class devices.
The Simple Service Discovery Protocol (SSDP) is a network protocol based on the Internet protocol suite for advertisement and discovery of network services and presence information. It accomplishes this without assistance of server-based configuration mechanisms, such as Dynamic Host Configuration Protocol (DHCP) or Domain Name System (DNS), and without special static configuration of a network host. SSDP is the basis of the discovery protocol of Universal Plug and Play (UPnP) and is intended for use in residential or small office environments. It was formally described in an IETF Internet Draft by Microsoft and Hewlett-Packard in 1999. Although the IETF proposal has since expired, SSDP was incorporated into the UPnP protocol stack, and a description of the final implementation is included in UPnP standards documents.
gtk-gnutella is a peer-to-peer file sharing application which runs on the gnutella network. gtk-gnutella uses the GTK+ toolkit for its graphical user interface. Released under the GNU General Public License, gtk-gnutella is free software.
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Internet Connection Sharing (ICS) is a Windows service that enables one Internet-connected computer to share its Internet connection with other computers on a local area network (LAN). The computer that shares its Internet connection serves as a gateway device, meaning that all traffic between other computers and the Internet go through this computer. ICS provides Dynamic Host Configuration Protocol (DHCP) and network address translation (NAT) services for the LAN computers.
In computer networking, port forwarding or port mapping is an application of network address translation (NAT) that redirects a communication request from one address and port number combination to another while the packets are traversing a network gateway, such as a router or firewall. This technique is most commonly used to make services on a host residing on a protected or masqueraded (internal) network available to hosts on the opposite side of the gateway, by remapping the destination IP address and port number of the communication to an internal host.
STUN is a standardized set of methods, including a network protocol, for traversal of network address translator (NAT) gateways in applications of real-time voice, video, messaging, and other interactive communications.
UDP hole punching is a commonly used technique employed in network address translation (NAT) applications for maintaining User Datagram Protocol (UDP) packet streams that traverse the NAT. NAT traversal techniques are typically required for client-to-client networking applications on the Internet involving hosts connected in private networks, especially in peer-to-peer, Direct Client-to-Client (DCC) and Voice over Internet Protocol (VoIP) deployments.
Network address translation traversal is a computer networking technique of establishing and maintaining Internet Protocol connections across gateways that implement network address translation (NAT).
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A middlebox is a computer networking device that transforms, inspects, filters, and manipulates traffic for purposes other than packet forwarding. Examples of middleboxes include firewalls, network address translators (NATs), load balancers, and deep packet inspection (DPI) devices.
In computer networking, a firewall pinhole is a port that is not protected by a firewall to allow a particular application to gain access to a service on a host in the network protected by the firewall.
NAT Port Mapping Protocol (NAT-PMP) is a network protocol for establishing network address translation (NAT) settings and port forwarding configurations automatically without user effort. The protocol automatically determines the external IPv4 address of a NAT gateway, and provides means for an application to communicate the parameters for communication to peers. Apple introduced NAT-PMP in 2005 by as part of the Bonjour specification, as an alternative to the more common ISO Standard Internet Gateway Device Protocol implemented in many NAT routers. The protocol was published as an informational Request for Comments (RFC) by the Internet Engineering Task Force (IETF) in RFC 6886.
Hole punching is a technique in computer networking for establishing a direct connection between two parties in which one or both are behind firewalls or behind routers that use network address translation (NAT). To punch a hole, each client connects to an unrestricted third-party server that temporarily stores external and internal address and port information for each client. The server then relays each client's information to the other, and using that information each client tries to establish direct connection; as a result of the connections using valid port numbers, restrictive firewalls or routers accept and forward the incoming packets on each side.
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Carrier-grade NAT, also known as large-scale NAT (LSN), is a type of network address translation (NAT) used by ISPs in IPv4 network design. With CGNAT, end sites, in particular residential networks, are configured with private network addresses that are translated to public IPv4 addresses by middlebox network address translator devices embedded in the network operator's network, permitting the sharing of small pools of public addresses among many end users. This essentially repeats the traditional customer-premise NAT function at the ISP level.
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