55-483: (Redirected from RAPT ) [REDACTED] Look up rapt in Wiktionary, the free dictionary. Rapt or RAPT may refer to: Acronyms [ edit ] Rehabilitation for Addicted Prisoners Trust (RAPt), a charity which helps people with drug and alcohol dependence move towards, achieve and maintain drug and crime-free lives Reverse Address and Port Translation ,
110-677: A group of public IP addresses. NAT hairpinning , also known as NAT loopback or NAT reflection , is a feature in many consumer routers where a machine on the LAN is able to access another machine on the LAN via the external IP address of the LAN/router (with port forwarding set up on the router to direct requests to the appropriate machine on the LAN). This notion is officially described in 2008, RFC 5128 . The following describes an example network: If
165-451: A patch available to enable RFC 4787 support but this has not yet been merged. The NAT traversal problem arises when peers behind different NATs try to communicate. One way to solve this problem is to use port forwarding . Another way is to use various NAT traversal techniques. The most popular technique for TCP NAT traversal is TCP hole punching . TCP hole punching requires the NAT to follow
220-572: A "short-term solution" to the two most compelling problems facing the IP Internet at that time: IP address depletion and scaling in routing. By 2004, NAT had become widespread. The simplest type of NAT provides a one-to-one translation of IP addresses (RFC 1631). RFC 2663 refers to this type of NAT as basic NAT , also called a one-to-one NAT . In this type of NAT, only the IP addresses, IP header checksum , and any higher-level checksums that include
275-563: A 2009 French dramatic film directed by Lucas Belvaux Rapt: la séparation des races , a 1934 film directed by Dimitri Kirsanoff Other uses [ edit ] " Rapt. Dept. ", a 2005 single/EP from Yourcodenameis:milo Rapt or Raptus, a king of the Hasdingi Vandals See also [ edit ] Raptio , Latin term referring to the large scale abduction of women Raptor (disambiguation) Rapture (disambiguation) Raptus (disambiguation) Topics referred to by
330-501: A 2009 French dramatic film directed by Lucas Belvaux Rapt: la séparation des races , a 1934 film directed by Dimitri Kirsanoff Other uses [ edit ] " Rapt. Dept. ", a 2005 single/EP from Yourcodenameis:milo Rapt or Raptus, a king of the Hasdingi Vandals See also [ edit ] Raptio , Latin term referring to the large scale abduction of women Raptor (disambiguation) Rapture (disambiguation) Raptus (disambiguation) Topics referred to by
385-512: A Symmetric NAT as having an Address- and Port-Dependent Mapping . For the second bullet in each row of the above table, RFC 4787 would also label Full-Cone NAT as having an Endpoint-Independent Filtering , Restricted-Cone NAT as having an Address-Dependent Filtering , Port-Restricted Cone NAT as having an Address and Port-Dependent Filtering , and Symmetric NAT as having either an Address-Dependent Filtering or Address and Port-Dependent Filtering . Other classifications of NAT behavior mentioned in
440-468: A checksum that covers all the data they carry, as well as the TCP or UDP header, plus a pseudo-header that contains the source and destination IP addresses of the packet carrying the TCP or UDP header. For an originating NAT to pass TCP or UDP successfully, it must recompute the TCP or UDP header checksum based on the translated IP addresses, not the original ones, and put that checksum into the TCP or UDP header of
495-490: A methodology for testing a device accordingly. However, these procedures have since been deprecated from standards status, as the methods are inadequate to correctly assess many devices. RFC 5389 standardized new methods in 2008 and the acronym STUN now represents the new title of the specification: Session Traversal Utilities for NAT . It is similar to an address restricted cone NAT, but the restriction includes port numbers. Many NAT implementations combine these types, so it
550-399: A packet is sent to 203.0.113.1 by a computer at 192.168.1.100 , the packet would normally be routed to the default gateway (the router) A router with the NAT loopback feature detects that 203.0.113.1 is the address of its WAN interface, and treats the packet as if coming from that interface. It determines the destination for that packet, based on DNAT (port forwarding) rules for
605-405: A private network. When a computer on the private (internal) network sends an IP packet to the external network, the NAT device replaces the internal source IP address in the packet header with the external IP address of the NAT device. PAT may then assign the connection a port number from a pool of available ports, inserting this port number in the source port field. The packet is then forwarded to
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#1733114509508660-646: A single local port with many remote hosts. This additional tracking increases implementation complexity and computing resources at the translation device. Because the internal addresses are all disguised behind one publicly accessible address, it is impossible for external hosts to directly initiate a connection to a particular internal host. Applications such as VOIP , videoconferencing , and other peer-to-peer applications must use NAT traversal techniques to function. Pure NAT, operating on IP alone, may or may not correctly parse protocols with payloads containing information about IP, such as ICMP . This depends on whether
715-488: A specific internal address and port. RFC 4787 makes a distinction between NAT mapping and NAT filtering. Section 4.1 of the RFC covers NAT mapping and specifies how an external IP address and port number should be translated into an internal IP address and port number. It defines Endpoint-Independent Mapping, Address-Dependent Mapping and Address and Port-Dependent Mapping, explains that these three possible choices do not relate to
770-519: A variation of Network Address Translation in computing Retractable Amphibious Pontoon Technology, a retractable pontoon system for the float plane industry being developed by Tigerfish Aviation RAPT1 or mTOR, the mammalian target of rapamycin protein RATP Group ( Régie Autonome des Transports Parisiens ), a public transport company based in Paris, France Films [ edit ] Rapt (film) ,
825-422: A variation of Network Address Translation in computing Retractable Amphibious Pontoon Technology, a retractable pontoon system for the float plane industry being developed by Tigerfish Aviation RAPT1 or mTOR, the mammalian target of rapamycin protein RATP Group ( Régie Autonome des Transports Parisiens ), a public transport company based in Paris, France Films [ edit ] Rapt (film) ,
880-412: Is PAT or NAT overloading and maps multiple private IP addresses to a single public IP address. Multiple addresses can be mapped to a single address because each private address is tracked by a port number. PAT uses unique source port numbers on the inside global IP address to distinguish between translations. PAT attempts to preserve the original source port. If this source port is already used, PAT assigns
935-514: Is a Cisco proposal that combines Address plus Port translation with tunneling of the IPv4 packets over an ISP provider's internal IPv6 network. In effect, it is an (almost) stateless alternative to carrier-grade NAT and DS-Lite that pushes the IPv4 address /port translation function (and the maintenance of NAT state) entirely into the existing customer premises equipment NAT implementation. Thus avoiding
990-520: Is also called port forwarding , or DMZ when used on an entire server , which becomes exposed to the WAN, becoming analogous to an undefended military demilitarized zone (DMZ). The meaning of the term SNAT varies by vendor: Secure network address translation (SNAT) is part of Microsoft's Internet Security and Acceleration Server and is an extension to the NAT driver built into Microsoft Windows Server . It provides connection tracking and filtering for
1045-478: Is better to refer to specific individual NAT behavior instead of using the Cone/Symmetric terminology. RFC 4787 attempts to alleviate confusion by introducing standardized terminology for observed behaviors. For the first bullet in each row of the above table, the RFC would characterize Full-Cone, Restricted-Cone, and Port-Restricted Cone NATs as having an Endpoint-Independent Mapping , whereas it would characterize
1100-517: Is different from Wikidata All article disambiguation pages All disambiguation pages rapt [REDACTED] Look up rapt in Wiktionary, the free dictionary. Rapt or RAPT may refer to: Acronyms [ edit ] Rehabilitation for Addicted Prisoners Trust (RAPt), a charity which helps people with drug and alcohol dependence move towards, achieve and maintain drug and crime-free lives Reverse Address and Port Translation ,
1155-464: Is different from Wikidata All article disambiguation pages All disambiguation pages Reverse Address and Port Translation 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 initially used to bypass
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#17331145095081210-489: Is forwarded to the inside network. Otherwise, if the destination port number of the incoming packet is not found in the translation table, the packet is dropped or rejected because the PAT device doesn't know where to send it. IEEE Reverse Address and Port Translation (RAPT or RAT) allows a host whose real IP address changes from time to time to remain reachable as a server via a fixed home IP address. Cisco 's RAPT implementation
1265-415: Is no need to use a third party (like STUN) to discover the NAT port since the application itself already knows the NAT port. However, if two internal hosts attempt to communicate with the same external host using the same port number, the NAT may attempt to use a different external IP address for the second connection or may need to forgo port preservation and remap the port. As of 2006 , roughly 70% of
1320-436: Is recommended where maximum application transparency is required while Address-Dependent Filtering is recommended where more stringent filtering behavior is most important. Some NAT devices are not yet compliant with RFC 4787 as they treat NAT mapping and filtering in the same way so that their configuration option for changing the NAT filtering method also changes the NAT mapping method (e.g. Netgate TNSR ). The PF firewall has
1375-503: The IP header ) and port number (within the Transport Layer header ) on the returned packet can be unambiguously mapped to the corresponding private network destination. RFC 2663 uses the term network address and port translation ( NAPT ) for this type of NAT. Other names include port address translation ( PAT ), IP masquerading , NAT overload , and many-to-one NAT . This is the most common type of NAT and has become synonymous with
1430-527: The NAT444 and statefulness problems of carrier-grade NAT, and also provides a transition mechanism for the deployment of native IPv6 at the same time with very little added complexity. Hosts behind NAT-enabled routers do not have end-to-end connectivity and cannot participate in some internet protocols. Services that require the initiation of TCP connections from the outside network, or that use stateless protocols such as those using UDP , can be disrupted. Unless
1485-439: The port preservation design for TCP. For a given outgoing TCP communication, the same port numbers are used on both sides of the NAT. NAT port preservation for outgoing TCP connections is crucial for TCP NAT traversal because, under TCP, one port can only be used for one communication at a time. Programs that bind distinct TCP sockets to ephemeral ports for each TCP communication, make NAT port prediction impossible for TCP. On
1540-459: The IP address are changed. Basic NAT can be used to interconnect two IP networks with incompatible addresses. Most network address translators map multiple private hosts to one publicly exposed IP address. Here is a typical configuration: All IP packets have a source IP address and a destination IP address. Typically, packets passing from the private network to the public network will have their source address modified, while packets passing from
1595-459: The IP address information in packets, NAT implementations may vary in their specific behavior in various addressing cases and their effect on network traffic. Vendors of equipment containing NAT implementations do not commonly document the specifics of NAT behavior. IPv4 uses 32-bit addresses, capable of uniquely addressing about 4.3 billion devices. By 1992, it became evident that that would not be enough. The 1994 RFC 1631 describes NAT as
1650-507: The NAT router makes a specific effort to support such protocols, incoming packets cannot reach their destination. Some protocols can accommodate one instance of NAT between participating hosts ("passive mode" FTP , for example), sometimes with the assistance of an application-level gateway (see § Applications affected by NAT ), but fail when both systems are separated from the internet by NAT. The use of NAT also complicates tunneling protocols such as IPsec because NAT modifies values in
1705-420: The NAT. Destination network address translation (DNAT) is a technique for transparently changing the destination IP address of a routed packet and performing the inverse function for any replies. Any router situated between two endpoints can perform this transformation of the packet. DNAT is commonly used to publish a service located in a private network on a publicly accessible IP address. This use of DNAT
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1760-434: The RFC include whether they preserve ports, when and how mappings are refreshed, whether external mappings can be used by internal hosts (i.e., its hairpinning behavior), and the level of determinism NATs exhibit when applying all these rules. Specifically, most NATs combine symmetric NAT for outgoing connections with static port mapping , where incoming packets addressed to the external address and port are redirected to
1815-446: The additional network connections needed for the FTP , ICMP , H.323 , and PPTP protocols as well as the ability to configure a transparent HTTP proxy server . Dynamic NAT, just like static NAT, is not common in smaller networks but is found within larger corporations with complex networks. Where static NAT provides a one-to-one internal to public static IP address mapping, dynamic NAT uses
1870-477: The clients in P2P networks employed some form of NAT. Every TCP and UDP packet contains a source port number and a destination port number. Each of those packets is encapsulated in an IP packet, whose IP header contains a source IP address and a destination IP address. The IP address/protocol/port number triple defines an association with a network socket . For publicly accessible services such as web and mail servers
1925-413: The destination. If the data were sent to port 80 and a DNAT rule exists for port 80 directed to 192.168.1.2 , then the host at that address receives the packet. If no applicable DNAT rule is available, the router drops the packet. An ICMP Destination Unreachable reply may be sent. If any DNAT rules were present, address translation is still in effect; the router still rewrites the source IP address in
1980-617: The external address of a network address translator. This is the address that its communication peers in the external network detect. Furthermore, it may be necessary to examine and categorize the type of mapping in use, for example when it is desired to set up a direct communication path between two clients both of which are behind separate NAT gateways. For this purpose, RFC 3489 specified a protocol called Simple Traversal of UDP over NATs ( STUN ) in 2003. It classified NAT implementations as full-cone NAT , (address) restricted-cone NAT , port-restricted cone NAT or symmetric NAT , and proposed
2035-399: The external network. The NAT device then makes an entry in a translation table containing the internal IP address, original source port, and the translated source port. Subsequent packets from the same internal source IP address and port number are translated to the same external source IP address and port number. The computer receiving a packet that has undergone NAT establishes a connection to
2090-421: The first available port number starting from the beginning of the appropriate port group 0–511, 512–1023, or 1024–65535. When there are no more ports available and there is more than one external IP address configured, PAT moves to the next IP address to try to allocate the original source port again. This process continues until it runs out of available ports and external IP addresses. Mapping of Address and Port
2145-411: The first packet of the fragmented set of packets. Alternatively, the originating host may perform path MTU Discovery to determine the packet size that can be transmitted without fragmentation and then set the don't fragment (DF) bit in the appropriate packet header field. This is only a one-way solution, because the responding host can send packets of any size, which may be fragmented before reaching
2200-551: The headers which interfere with the integrity checks done by IPsec and other tunneling protocols. End-to-end connectivity has been a core principle of the Internet, supported, for example, by the Internet Architecture Board . Current Internet architectural documents observe that NAT is a violation of the end-to-end principle , but that NAT does have a valid role in careful design. There is considerably more concern with
2255-426: The internet. Ports are endpoints of communication unique to that host, so a connection through the NAT device is maintained by the combined mapping of port and IP address. A private address on the inside of the NAT is mapped to an external public address. Port address translation (PAT) resolves conflicts that arise when multiple hosts happen to use the same source port number to establish different external connections at
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2310-408: The main phone number is the public IP address, and the individual extensions are unique port numbers. With NAT, all communications sent to external hosts actually contain the external IP address and port information of the NAT device instead of internal host IP addresses or port numbers. NAT only translates IP addresses and ports of its internal hosts, hiding the true endpoint of an internal host on
2365-443: 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 . As network address translation modifies
2420-468: The network would be unable to browse a website hosted within. Protocols not based on TCP and UDP require other translation techniques. An additional benefit of one-to-many NAT is that it mitigates IPv4 address exhaustion by allowing entire networks to be connected to the Internet using a single public IP address. Network address and port translation may be implemented in several ways. Some applications that use IP address information may need to determine
2475-467: The other hand, for UDP, NATs do not need port preservation. Indeed, multiple UDP communications (each with a distinct endpoint ) can occur on the same source port, and applications usually reuse the same UDP socket to send packets to distinct hosts. This makes port prediction straightforward, as it is the same source port for each packet. Furthermore, port preservation in NAT for TCP allows P2P protocols to offer less complexity and less latency because there
2530-537: The payload is interpreted by a host on the inside or outside of the translation. Basic protocols as TCP and UDP cannot function properly unless NAT takes action beyond the network layer. IP packets have a checksum in each packet header, which provides error detection only for the header. IP datagrams may become fragmented and it is necessary for a NAT to reassemble these fragments to allow correct recalculation of higher-level checksums and correct tracking of which packets belong to which connection. TCP and UDP, have
2585-402: The port and IP address specified in the altered packet, oblivious to the fact that the supplied address is being translated. Upon receiving a packet from the external network, the NAT device searches the translation table based on the destination port in the packet header. If a match is found, the destination IP address and port number is replaced with the values found in the table and the packet
2640-495: The port number is important. For example, port 443 connects through a socket to the web server software and port 465 to a mail server's SMTP daemon . The IP address of a public server is also important, similar in global uniqueness to a postal address or telephone number. Both IP address and port number must be correctly known by all hosts wishing to successfully communicate. Private IP addresses as described in RFC 1918 are usable only on private networks not directly connected to
2695-403: The public network back to the private network will have their destination address modified. To avoid ambiguity in how replies are translated, further modifications to the packets are required. The vast bulk of Internet traffic uses Transmission Control Protocol (TCP) or User Datagram Protocol (UDP). For these protocols, the port numbers are changed so that the combination of IP address (within
2750-404: The same term [REDACTED] This disambiguation page lists articles associated with the title Rapt . If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=Rapt&oldid=881208718 " Category : Disambiguation pages Hidden categories: Short description
2805-404: The same term [REDACTED] This disambiguation page lists articles associated with the title Rapt . If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=Rapt&oldid=881208718 " Category : Disambiguation pages Hidden categories: Short description
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#17331145095082860-406: The same time. A NAT device is similar to a phone system at an office that has one public telephone number and multiple extensions. Outbound phone calls made from the office all appear to come from the same telephone number. However, an incoming call that does not specify an extension cannot be automatically transferred to an individual inside the office. In this scenario, the office is a private LAN,
2915-462: The security of the NAT as security is determined by the filtering behavior and then specifies "A NAT MUST have an 'Endpoint-Independent Mapping' behavior." Section 5 of the RFC covers NAT filtering and describes what criteria are used by the NAT to filter packets originating from specific external endpoints. The options are Endpoint-Independent Filtering, Address-Dependent Filtering and Address and Port-Dependent Filtering. Endpoint-Independent Filtering
2970-402: The term NAT in common usage. This method allows communication through the router only when the conversation originates in the private network, since the initial originating transmission is what establishes the required information in the translation tables. Thus a web browser within the private network would be able to browse websites that are outside the network, whereas web browsers outside
3025-411: The use of IPv6 NAT, and many IPv6 architects believe IPv6 was intended to remove the need for NAT. An implementation that only tracks ports can be quickly depleted by internal applications that use multiple simultaneous connections such as an HTTP request for a web page with many embedded objects. This problem can be mitigated by tracking the destination IP address in addition to the port thus sharing
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