Cloudflare Docs
Edit this page on GitHub
Set theme to dark (⇧+D)


Review the definitions for terms used across Cloudflare’s Spectrum documentation.

ACK (Acknowledge)The final step in the TCP three-way handshake, confirming the establishment of a connection.
FTP (File Transfer Protocol)A standard network protocol used for transferring files from one host to another over a TCP-based network.
FTPS (File Transfer Protocol Secure)An extension of FTP that adds support for the Transport Layer Security (TLS) or Secure Sockets Layer (SSL) cryptographic protocols.
layer 3The network layer in the OSI model, responsible for logical addressing, routing, and forwarding of data between devices on different networks.
layer 4The transport layer in the OSI model, managing end-to-end communication, error-checking, and flow control.
MQTT (Message Queuing Telemetry Transport)A lightweight, publish-subscribe messaging protocol often used for communication in the Internet of Things (IoT) and other resource-constrained scenarios.
OSI model (Open Systems Interconnection model)A conceptual framework that standardizes the functions of a telecommunication or computing system into seven abstraction layers.
proxy protocolA protocol used by network proxies to convey client connection information to the destination server, facilitating proper handling of client requests.
reverse proxyA server that handles requests on behalf of clients, forwarding them to backend servers and managing tasks like load balancing and security.
SFTP (Secure File Transfer Protocol)A secure file transfer protocol that uses the Secure Socket Shell (SSH) protocol for encryption and authentication.
SMTP Server (Simple Mail Transfer Protocol Server)A server responsible for sending, receiving, and relaying email messages over a network, following the SMTP protocol.
SYN (Synchronize)The initial step in establishing a TCP connection, where a device requests a connection with another by sending a SYN packet.
SYN-ACK (Synchronize-Acknowledge)The second step in the TCP three-way handshake, where the server responds to a SYN request with a SYN-ACK packet.
TCP (Transmission Control Protocol)A connection-oriented protocol in the transport layer of the Internet Protocol Suite, providing reliable and ordered delivery of data between devices.
UDP (User Datagram Protocol)UDP (User Datagram Protocol) is a connectionless transport layer protocol that provides fast and lightweight data transmission between devices on a network, prioritizing speed over reliability.