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SIP URI Scheme
The SIP URI scheme is a Uniform Resource Identifier (URI) scheme for the Session Initiation Protocol (SIP) multimedia communications protocol. A SIP address is a URI that addresses a specific telephone extension on a voice over IP system. Such a number could be a private branch exchange or an E.164 telephone number dialled through a specific gateway. The scheme was defined in . Operation A SIP address is written in user@domain.tld format in a similar fashion to an email address. An address like: : sip:1-999-123-4567@voip-provider.example.net instructs a SIP client to use the NAPTR and SRV schemes to look up the SIP server associated with the DNS name voip-provider.example.net and connect to that server. If those records are not found, but the name is associated with an IP address, the client will directly contact the SIP server at that IP address on port 5060, by default using the UDP transport protocol. It will ask the server (which may be a gateway) to be connected to the dest ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Uniform Resource Identifier
A Uniform Resource Identifier (URI) is a unique sequence of characters that identifies a logical or physical resource used by web technologies. URIs may be used to identify anything, including real-world objects, such as people and places, concepts, or information resources such as web pages and books. Some URIs provide a means of locating and retrieving information resources on a network (either on the Internet or on another private network, such as a computer filesystem or an Intranet); these are Uniform Resource Locators (URLs). A URL provides the location of the resource. A URI identifies the resource by name at the specified location or URL. Other URIs provide only a unique name, without a means of locating or retrieving the resource or information about it, these are Uniform Resource Names (URNs). The web technologies that use URIs are not limited to web browsers. URIs are used to identify anything described using the Resource Description Framework (RDF), for example, con ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Softphone
A softphone is a software program for making telephone calls over the Internet using a general purpose computer rather than dedicated hardware. The softphone can be installed on a piece of equipment such as a desktop, mobile device, or other computer and allows the user to place and receive calls without requiring an actual telephone set. Often, a softphone is designed to behave like a traditional telephone, sometimes appearing as an image of a handset, with a display panel and buttons with which the user can interact. A softphone is usually used with a headset connected to the sound card of the PC or with a USB phone. Applications See Comparison of VoIP software Communication protocols To communicate, both end-points must support the same voice-over-IP protocol, and at least one common audio codec. Many service providers use the Session Initiation Protocol (SIP) standardized by the Internet Engineering Task Force (IETF). Skype, a popular service, uses proprietary protocols, an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telephone Number Mapping
Telephone number mapping is a system of unifying the international telephone number system of the public switched telephone network with the Internet addressing and identification name spaces. Internationally, telephone numbers are systematically organized by the E.164 standard, while the Internet uses the Domain Name System (DNS) for linking domain names to IP addresses and other resource information. Telephone number mapping systems provide facilities to determine applicable Internet communications servers responsible for servicing a given telephone number using DNS queries. The most prominent facility for telephone number mapping is the E.164 number to URI mapping (ENUM) standard. It uses special DNS record types to translate a telephone number into a Uniform Resource Identifier (URI) or IP address that can be used in Internet communications. Rationale Being able to dial telephone numbers the way customers have come to expect is considered crucial for the convergence of clas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Federated VoIP
Federated VoIP is a form of packetized voice telephony that uses voice over IP between autonomous domains in the public Internet without the deployment of central virtual exchange points or switching centers for traffic routing. Federated VoIP uses decentralized addressing systems, such as ENUM, for location and identity information of participants and implements secure, trusted communications (TLS) for identify verification. Background The traditional telephone networks are based on the principle of point-to-point communications, for example, an office building sends and receives phone calls over an ISDN line to the telephone exchange. Early Voice over IP deployments have copied this model, sending phone calls over SIP Trunking (a virtual equivalent of ISDN) to an Internet telephony service provider (ITSP) (a virtual telephone exchange). Such paradigms have striven to emulate many of the aspects of traditional telephony, such as the telephone number. Federation Although the use of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transport Layer Security
Transport Layer Security (TLS) is a cryptographic protocol designed to provide communications security over a computer network. The protocol is widely used in applications such as email, instant messaging, and voice over IP, but its use in securing HTTPS remains the most publicly visible. The TLS protocol aims primarily to provide security, including privacy (confidentiality), integrity, and authenticity through the use of cryptography, such as the use of certificates, between two or more communicating computer applications. It runs in the presentation layer and is itself composed of two layers: the TLS record and the TLS handshake protocols. The closely related Datagram Transport Layer Security (DTLS) is a communications protocol providing security to datagram-based applications. In technical writing you often you will see references to (D)TLS when it applies to both versions. TLS is a proposed Internet Engineering Task Force (IETF) standard, first defined in 1999, and the c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fail2ban
Fail2ban is an intrusion prevention software framework. Written in the Python programming language, it is designed to prevent against brute-force attacks. It is able to run on POSIX systems that have an interface to a packet-control system or firewall installed locally, such as iptables or TCP Wrapper. Functionality Fail2ban operates by monitoring log files (e.g. , , etc.) for selected entries and running scripts based on them. Most commonly this is used to block selected IP addresses that may belong to hosts that are trying to breach the system's security. It can ban any host IP address that makes too many login attempts or performs any other unwanted action within a time frame defined by the administrator. Includes support for both IPv4 and IPv6. Optionally longer bans can be custom-configured for "recidivist" abusers that keep coming back. Fail2ban is typically set up to unban a blocked host within a certain period, so as to not "lock out" any genuine connections that may have ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Firewall (computing)
In computing, a firewall is a network security system that monitors and controls incoming and outgoing network traffic based on predetermined security rules. A firewall typically establishes a barrier between a trusted network and an untrusted network, such as the Internet. History The term ''firewall'' originally referred to a wall intended to confine a fire within a line of adjacent buildings. Later uses refer to similar structures, such as the metal sheet separating the engine compartment of a vehicle or aircraft from the passenger compartment. The term was applied in the late 1980s to network technology that emerged when the Internet was fairly new in terms of its global use and connectivity. The predecessors to firewalls for network security were routers used in the late 1980s. Because they already segregated networks, routers could apply filtering to packets crossing them. Before it was used in real-life computing, the term appeared in the 1983 computer-hacking movie ' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
North American Numbering Plan
The North American Numbering Plan (NANP) is a telephone numbering plan for twenty-five regions in twenty countries, primarily in North America and the Caribbean. This group is historically known as World Zone 1 and has the international calling code ''1''. Some North American countries, most notably Mexico, do not participate in the NANP. The NANP was originally devised in the 1940s by the American Telephone and Telegraph Company (AT&T) for the Bell System and the independent telephone operators in North America. The goal was to unify the diverse local numbering plans that had been established in the preceding decades and prepare the continent for direct-dialing of calls by customers without the involvement of telephone operators. AT&T continued to administer the numbering plan until the breakup of the Bell System, when administration was delegated to the North American Numbering Plan Administrator (NANPA), a service that has been procured from the private sector by the Fede ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Off-premises Extension
{{Unreferenced, date=December 2009 An off-premises extension (OPX), sometimes also known as off-premises station (OPS), is an extension telephone at a location distant from its servicing exchange. One type of off-premises extension, connected to a private branch exchange (PBX), is generally used to provide employees with access to a company telephone system while they are out of the office. Off-premises extensions are used in distributed environments, serving locations that are too far from the PBX to be served by on-premises wiring. Another type of off-premises extension, connected to a public telephone exchange, is generally used to allow a private phone line to ring at a second location. For example, the owner of a business may have an OPX for their home phone at the business location, allowing them to avoid missing calls to the home phone. Telephone service providers charge a significant monthly rate for an OPX, partly calculated by the distance; in extreme cases, the distanc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brute Force Attack
In cryptography, a brute-force attack consists of an attacker submitting many passwords or passphrases with the hope of eventually guessing correctly. The attacker systematically checks all possible passwords and passphrases until the correct one is found. Alternatively, the attacker can attempt to guess the key which is typically created from the password using a key derivation function. This is known as an exhaustive key search. A brute-force attack is a cryptanalytic attack that can, in theory, be used to attempt to decrypt any encrypted data (except for data encrypted in an information-theoretically secure manner). Such an attack might be used when it is not possible to take advantage of other weaknesses in an encryption system (if any exist) that would make the task easier. When password-guessing, this method is very fast when used to check all short passwords, but for longer passwords other methods such as the dictionary attack are used because a brute-force search ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caller ID Spoofing
Caller ID spoofing is the practice of causing the telephone network to indicate to the receiver of a call that the originator of the call is a station other than the true originating station. This can lead to a caller ID Caller identification (Caller ID) is a telephone service, available in analog and digital telephone systems, including voice over IP (VoIP), that transmits a caller's telephone number to the called party's telephone equipment when the call is ... display showing a phone number different from that of the telephone from which the call was placed. The term is commonly used to describe situations in which the motivation is considered malicious by the originator. One effect of the widespread availability of Caller ID spoofing is that, as AARP published in 2019, "you can no longer trust call ID." History Caller ID spoofing has been available for years to people with a specialized digital connection to the telephone company, called an Integrated Services Digit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
VoIP Spam
VoIP spam or SPIT (spam over Internet telephony) is unsolicited, automatically dialed telephone calls, typically using voice over Internet Protocol (VoIP) technology. VoIP systems, like e-mail and other Internet applications, are susceptible to abuse by malicious parties who initiate unsolicited and unwanted communications, such as telemarketers and prank callers. VoIP calling rates are cheap, and the technology provides convenient, often free tools, such as Asterisk and other applications. The primary underlying technology driving this threat is the Session Initiation Protocol (SIP), which is a standard for VoIP telecommunications. Various techniques have been devised to detect spam calls; some take effect even before the recipient has answered a call to disconnect it. These techniques rely on statistical analysis of the features of the call, such as the originating IP address, or features of the signalling and media messages. Character VoIP spam is characterized as unsolicite ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
