Term 541
Screened subnet
A screened subnet is a network architecture that places a buffer network, often called a DMZ, between an internal trusted network and an external untrusted network, using two firewalls to control traffic.
Acronym study
Terms 541–570 of 716 CCNA acronyms and key terms. Each entry includes a plain-English definition and a link to the full 800-word glossary page with exam context and practice questions.
Term 541
A screened subnet is a network architecture that places a buffer network, often called a DMZ, between an internal trusted network and an external untrusted network, using two firewalls to control traffic.
Term 542
SD-WAN is a software-defined approach to managing wide-area networks that improves performance, lowers cost, and simplifies connectivity between branch offices and data centers.
Term 543
Software-Defined Networking (SDN) is an approach to network management that separates the control plane (decision-making) from the data plane (traffic forwarding), allowing centralized, programmable network control.
Term 544
AWS Secrets Manager is a fully managed service that helps you protect access to your applications, services, and IT resources by securely storing, rotating, and controlling access to secrets like database passwords, API keys, and credentials.
Term 545
Secure Shell (SSH) is a network protocol that provides a secure, encrypted way to access and manage remote computers over an unsecured network.
Term 546
A secure web gateway (SWG) is a security solution that protects users and organizations from web-based threats by filtering internet traffic, enforcing security policies, and blocking access to malicious or unauthorized websites.
Term 547
A security group is a virtual firewall that controls inbound and outbound traffic to AWS resources, such as EC2 instances, based on defined rules.
Term 548
sed is a stream editor used in Unix and Linux to perform basic text transformations on an input stream, such as finding and replacing text, deleting lines, or inserting content.
Term 549
A segment is a division of a larger network, such as a collision domain, broadcast domain, or a portion of a TCP data stream, used to organize traffic and improve performance.
Term 550
A service endpoint is a specific network address (URL or IP/port) that client applications use to access the functionality or data of a cloud or web service.
Term 551
A service failure is an interruption or degradation of a software application, system, or network component that prevents it from delivering its intended function to users or other systems.
Term 552
A Service Set Identifier (SSID) is the public name of a Wi-Fi network that devices use to identify and connect to it.
Term 553
Session Initiation Protocol (SIP) is a signaling protocol used to start, maintain, and end voice and video calls over IP networks.
Term 554
sFlow is a network monitoring technology that samples packets and exports traffic statistics to a central collector for analyzing network performance and security.
Term 555
SFTP (SSH File Transfer Protocol) is a secure method for transferring files over a network using an encrypted SSH connection.
Term 556
SHA-256 is a cryptographic hash function that takes any input data and produces a fixed 256-bit string of characters, like a unique digital fingerprint, used to verify data integrity and secure passwords.
Term 557
SHA-3 is the latest member of the Secure Hash Algorithm family, a standardized cryptographic hash function used to ensure data integrity and authenticity in IT systems.
Term 558
A Shared VPC allows multiple projects or accounts within a cloud environment to use the same Virtual Private Cloud (VPC) network, enabling centralized management and isolation of resources.
Term 559
A shield in IT networking is a conductive layer around a cable or device that blocks electromagnetic interference to protect signal integrity.
Term 560
Shielded Twisted Pair (STP) is a type of copper cabling that uses a metallic shield around twisted wire pairs to reduce electromagnetic interference and protect data signals.
Term 561
Shutdown mode is a port security state on a switch port that disables the port when a security violation occurs, such as when an unauthorized device attempts to connect.
Term 562
A Signed URL is a time-limited, authenticated web link that grants temporary access to a private resource without requiring the user to log in.
Term 563
Simple Mail Transfer Protocol (SMTP) is the standard internet protocol used for sending and relaying email messages from a client to a server or between servers.
Term 564
SLAAC (Stateless Address Autoconfiguration) is a method that allows an IPv6 device to automatically generate its own IP address without needing a centralized server like DHCP.
Term 565
Slow performance means a computer, application, or network takes longer than expected to complete tasks, often due to resource limits, software conflicts, or hardware degradation.
Term 566
A Small Form-factor Pluggable (SFP) is a compact, hot-swappable transceiver module used to connect networking devices to fiber optic or copper cables, converting electrical signals into light signals for data transmission.
Term 567
SMB (Server Message Block) is a network protocol used primarily for sharing files, printers, and other resources between computers over a local network.
Term 568
SMTP (Simple Mail Transfer Protocol) is the standard internet protocol used to send emails from a client to a server or between email servers.
Term 569
A snapshot is a point-in-time copy of a system's data or state, used for backup, recovery, or testing without disrupting the original.
Term 570
SNMP (Simple Network Management Protocol) is an application-layer protocol used to collect and organize information about managed devices on IP networks and to modify that information to change device behavior.