Instruct: Given a question, retrieve passages that can help answer the question.
Query: What is the first part of an IP address?
An IP address serves two principal functions. It identifies the host, or more specifically its network interface, and it provides the location of the host in the network, and thus the capability of establishing a path to that host. Its role has been characterized as follows: "A name indicates what we seek. An address indicates where it is. A route indicates how to get there."
The header of each IP packet contains the IP address of the sending host, and that of the destination host.
No formal specification of this textual IP address representation exists. The first mention of this format in RFC documents was in RFC 780 for the Mail Transfer Protocol published May 1981, in which the IP address was supposed to be enclosed in brackets or represented as a 32bit decimal integer prefixed by a pound sign. A table in RFC 790 ("Assigned Numbers") used the dotted decimal format, zero-padding each number to three digits. RFC 1123 ("Requirements for Internet Hosts – Application and Support") from October 1989 mentions a requirement on host software to accept “IP address in dotted-decimal ("#.#.#.#") form”, although it notes “[t]his last requirement is not intended to specify the complete syntactic form for entering a dotted-decimal host number”. A separate IETF draft to define textual representation of IP addresses expired.
The first specification of IP tunneling was in RFC 1075, which described DVMRP, the first IP multicast routing protocol. Because multicast used special IPv4 addresses, testing DVMRP required a way to get IP datagrams across portions of the Internet that did not yet recognize multicast addresses. This was solved by IP tunneling. The first approach to IP tunneling used an IP Loose Source Route and Record (LSRR) Option to hide the multicast address from the non-multicast aware routers. A multicast-aware destination router would remove the LSRR option from the packet and restore the multicast IP address to the packet's IP destination field. The other approach in the DVMRP specification was IP in IP, as described above. IP in IP soon became the preferred approach, and was later put to use in the Mbone.
IP stacks need to correlate Ethernet addresses (MAC address) and IP addresses, using a specific protocol named ARP. When a RTP-MIDI application wants to send a packet to a remote device, it must locate it first on the network, since Ethernet does not understand IP-related concepts, in order to create the transmission path between the routers/switches. This is done automatically by the IP stack by sending first an ARP (Address Recognition Protocol) request. When the destination device recognizes its own IP address in the ARP packet, it sends back an ARP reply with its MAC address. The IP stack can then send the RTP-MIDI packet. The next RTP-MIDI packets do not need the ARP sequence anymore, unless the link becomes inactive for a few minutes, which clears the ARP entry in the sender's routing table.
Advertisers may also deliver ads based on a user's suspected geography through geotargeting. A user's IP address communicates some geographic information (at minimum, the user's country or general region). The geographic information from an IP can be supplemented and refined with other proxies or information to narrow the range of possible locations. For example, with mobile devices, advertisers can sometimes use a phone's GPS receiver or the location of nearby mobile towers. Cookies and other persistent data on a user's machine may provide help narrowing a user's location further.
Hosts
Classful network design served its purpose in the startup stage of the Internet, but it lacked scalability in the face of the rapid expansion of networking in the 1990s. The class system of the address space was replaced with Classless Inter-Domain Routing (CIDR) in 1993. CIDR is based on variable-length subnet masking (VLSM) to allow allocation and routing based on arbitrary-length prefixes. Today, remnants of classful network concepts function only in a limited scope as the default configuration parameters of some network software and hardware components (e.g. netmask), and in the technical jargon used in network administrators' discussions.
IP address spoofing is most frequently used in denial-of-service attacks, where the objective is to flood the target with an overwhelming volume of traffic, and the attacker does not care about receiving responses to the attack packets. Packets with spoofed IP addresses are more difficult to filter since each spoofed packet appears to come from a different address, and they hide the true source of the attack. Denial of service attacks that use spoofing typically randomly choose addresses from the entire IP address space, though more sophisticated spoofing mechanisms might avoid unroutable addresses or unused portions of the IP address space. The proliferation of large botnets makes spoofing less important in denial of service attacks, but attackers typically have spoofing available as a tool, if they want to use it, so defenses against denial-of-service attacks that rely on the validity of the source IP address in attack packets might have trouble with spoofed packets. Backscatter, a technique used to observe denial-of-service attack activity in the Internet, relies on attackers' use of IP spoofing for its effectiveness.
Group D
"Charging function addresses" are addresses distributed to each IMS entities and provide a common location for each entity to send charging information. "charging data function" (CDF) addresses are used for offline billing and "Online Charging Function" (OCF) for online billing.IMS-based PES (PSTN Emulation System) provides IP networks services to analog devices. IMS-based PES allows non-IMS devices to appear to IMS as normal SIP users. Analog terminal using standard analog interfaces can connect to IMS-based PES in two ways:
The Sun 1,447,959 -7%
Group C
The World Wide Web, also known as the WWW and the Web, is an information space where documents and other web resources are identified by Uniform Resource Locators (URLs), interlinked by hypertext links, and accessible via the Internet. English scientist Tim Berners-Lee invented the World Wide Web in 1989. He wrote the first web browser in 1990 while employed at CERN near Geneva, Switzerland. The browser was released outside CERN in 1991, first to other research institutions starting in January 1991 and to the general public on the Internet in August 1991.
In August 2007, a tool called WikiScanner—developed by Virgil Griffith, a visiting researcher from the Santa Fe Institute in New Mexico—was released to match edits to the encyclopedia by non-registered users with an extensive database of IP addresses. News stories appeared about IP addresses from various organizations such as the Central Intelligence Agency, the National Republican Congressional Committee, the Democratic Congressional Campaign Committee, Diebold, Inc. and the Australian government being used to make edits to Wikipedia articles, sometimes of an opinionated or questionable nature. Another story stated that an IP address from the BBC itself had been used to vandalize the article on George W. Bush. The BBC quoted a Wikipedia spokesperson as praising the tool: "We really value transparency and the scanner really takes this to another level. Wikipedia Scanner may prevent an organisation or individuals from editing articles that they're really not supposed to." Not everyone hailed WikiScanner as a success for Wikipedia. Oliver Kamm, in a column for "The Times", argued instead that:
There are 70 primary Interstate Highways in the Interstate Highway System, a network of controlled-access freeways in the United States. They are assigned one- or two-digit route numbers, whereas their associated "auxiliary" Interstate Highways receive three-digit route numbers. Typically, odd-numbered Interstates run south-north, with lower numbers in the west and higher numbers in the east; even-numbered Interstates run west-east, with lower numbers in the south and higher numbers in the north. Highways whose route numbers are divisible by "5" usually represent major coast-to-coast or border-to-border routes (ex. I-10 travels from Santa Monica, California, to Jacksonville, Florida, traveling from the Pacific to Atlantic oceans). Additionally, auxiliary highways have their numbering system where a different number prefixes the number of its parent highway.
It provided an explanation of what the World Wide Web was, and how people could use a browser and set up a web server, as well as how to get started with your own website. In a list of 80 cultural moments that shaped the world, chosen by a panel of 25 eminent scientists, academics, writers, and world leaders, the invention of the World Wide Web was ranked number one, with the entry stating, "The fastest growing communications medium of all time, the internet has changed the shape of modern life forever. We can connect with each other instantly, all over the world".
The basic type of judicial division of Portugal is the "comarca", corresponding to the territorial area of jurisdiction of a judicial court of first instance.
The World Wide Web Virtual Library was the first index of content on the World Wide Web and still operates as a directory of e-texts and information sources on the web. It was started by Tim Berners-Lee creator of HTML and the World Wide Web itself, in 1991 at CERN in Geneva. Unlike commercial index sites, it is run by a loose confederation of volunteers, who compile pages of key links for particular areas in which they are expert. It is sometimes informally referred to as the "WWWVL", the "Virtual Library" or just "the VL".
HTTP is a stateless protocol. A stateless protocol does not require the HTTP server to retain information or status about each user for the duration of multiple requests. However, some web applications implement states or server side sessions using for instance HTTP cookies or hidden variables within web forms.
Apple has been promoting HTML5 as an alternative to Flash for video and other content on the iOS, citing performance reasons for not allowing Adobe Flash Player to be installed on iOS devices, including the iPhone, iPod touch and iPad. Flash applications can be packaged as native iOS applications via the Adobe Integrated Runtime and the iOS Packager.
Ivan Pope (1961-) is a British technologist who was involved with a number of early internet developments in the UK and across the world, and invented the "cybercafe" at London's Institute of Contemporary Arts. He was a founder of two of the first internet magazines, The World Wide Web Newsletter, and later .net magazine in the UK. In 1994 he founded Webmedia to professionalise the process of web site design and build. In 1995 he was involved with the creation of the domain name management company NetNames. Pope is now a writer and a noted proponent of the dérive.
IP networks may be divided into subnetworks in both IPv4 and IPv6. For this purpose, an IP address is recognized as consisting of two parts: the "network prefix" in the high-order bits and the remaining bits called the "rest field", "host identifier", or "interface identifier" (IPv6), used for host numbering within a network. The subnet mask or CIDR notation determines how the IP address is divided into network and host parts.
The first deployment scenario is where the network operator provides a hybrid CPE router to each subscriber but no specialised equipment in the operator's network. There are two possible configurations for IP addresses. A first deployment scenario is to allocate different IP addresses to the wired and wireless interfaces. In this case, the hybrid CPE router needs to load-balance intelligently the packets over the two networks. In particular, it must ensure that all packets belonging to a given TCP connection are sent over the same interface. A second deployment scenario is to allocate the same IP address to both the wired and the wireless networks and configure the routing in these networks to ensure that packets or correctly routed.
The term "subnet mask" is only used within IPv4. Both IP versions however use the CIDR concept and notation. In this, the IP address is followed by a slash and the number (in decimal) of bits used for the network part, also called the "routing prefix". For example, an IPv4 address and its subnet mask may be and , respectively. The CIDR notation for the same IP address and subnet is , because the first 24 bits of the IP address indicate the network and subnet.
The hosts file contains lines of text consisting of an IP address in the first text field followed by one or more host names. Each field is separated by white space – tabs are often preferred for historical reasons, but spaces are also used. Comment lines may be included; they are indicated by an octothorpe (#) in the first position of such lines. Entirely blank lines in the file are ignored. For example, a typical hosts file may contain the following:
This example only contains entries for the loopback addresses of the system and their host names, a typical default content of the hosts file. The example illustrates that an IP address may have multiple host names ("localhost" and "loopback"), and that a host name may be mapped to both IPv4 and IPv6 IP addresses, as shown on the first and second lines respectively.