Computer Networks

IP PBX (Internet Protocol Private Branch Exchange) is the modern system for routing and switching VoIP calls within organizations. Unlike traditional EPABX systems that use analog lines, IP PBX uses digital IP networks for voice communication. It enables features like voicemail, call forwarding, and auto-attendant over internet protocols.

Web servers typically listen on port 80 for standard HTTP traffic. This is the well-known port assigned for HTTP by IANA. Ports 100 and 25 are used for other services (25 is SMTP for email), and 133 is not a standard web server port. Port 80 is the default port that web browsers use when no port is specified in a URL.

ECP stands for Extended Capabilities Port, an advanced parallel port protocol that improves upon the original Centronics parallel port design. ECP supports bidirectional communication, higher data transfer rates, and DMA (Direct Memory Access) for improved performance with printers and other peripherals. The other options (Extra Compatible Part, Extended Connection Port, External Cordless Peripheral) are incorrect expansions.

Vinton Cerf, often called one of the 'fathers of the Internet,' co-developed TCP/IP protocols in 1973 along with Bob Kahn. The other names listed (Ben Johnson, Jack Shewzhen, Mitchel Frook) are not associated with this foundational internet development.

ICMP stands for Internet Control Message Protocol, which is a network layer protocol used for error reporting and diagnostic functions in IP networks. It's commonly used by tools like ping and traceroute to test network connectivity and diagnose problems. ICMP messages are typically generated by routers or hosts when network errors occur. Options A, B, and C are incorrect as they don't represent the actual meaning of the ICMP acronym.

SSL (Secure Sockets Layer) is a cryptographic protocol designed to provide secure communication over computer networks. It operates at the transport layer to encrypt data between client and server, ensuring privacy and data integrity. SSL was the predecessor to TLS (Transport Layer Security).

LCP (Link Control Protocol) is a component of PPP (Point-to-Point Protocol) used to establish, configure, maintain, and terminate point-to-point connections. It handles link quality monitoring and parameter negotiation between connected devices.

PPTP stands for Point-to-Point Tunneling Protocol. It is a network protocol used to implement VPN tunnels between public networks. It was developed by a consortium including Microsoft and is one of the oldest VPN protocols.

NIC stands for Network Interface Card, a hardware component that connects a computer to a network. It provides the physical interface between the computer's circuitry and the network cable or wireless connection.

NAT (Network Address Translation) is a method used by routers to remap IP addresses. It allows multiple devices on a local network to share a single public IP address when accessing the internet, conserving IP addresses and improving security.

ICANN (Internet Corporation for Assigned Names and Numbers) coordinates global DNS and IP address allocation. IANA is a department under ICANN. Domain name warehousing is a different practice.

SSL stands for Secure Socket Layer, a cryptographic protocol designed to provide secure communication over a computer network. It creates an encrypted link between a web server and browser, protecting sensitive data in transit. Note that SSL has been deprecated in favor of TLS (Transport Layer Security), but the term SSL is still widely used.

iptables is the Linux firewall tool that allows administrators to configure rules for allowing or blocking network traffic based on IP addresses, ports, and protocols. It operates at the kernel level to control network access to and from the system.

GPRS stands for General Packet Radio Service. It's a mobile data service that enables packet-based communication. Option A is correct - 'General' (not Global), 'Packet' (data transmission method), and 'Service' (not System or Render). GPRS is a 2.5G technology.