Term 241
Hello packet
A Hello packet is a small OSPF message sent by routers to discover neighboring routers, establish and maintain neighbor relationships, and elect a Designated Router on multiaccess networks.
Acronym study
Terms 241–270 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 241
A Hello packet is a small OSPF message sent by routers to discover neighboring routers, establish and maintain neighbor relationships, and elect a Designated Router on multiaccess networks.
Term 242
The Hello timer is the interval at which an OSPF router sends Hello packets to discover and maintain neighbor relationships on a network segment.
Term 243
A here document is a scripting feature that allows you to embed a block of text or code directly inside a script without needing to use multiple echo or print statements, and it can include variables and special characters.
Term 244
High availability is a system design approach that aims to keep applications and services operational and accessible with minimal downtime, even when some components fail.
Term 245
A network device condition where processor utilisation reaches levels that degrade performance or cause service interruptions.
Term 246
High disk usage is a condition where a computer's storage drive is working near or at its maximum capacity, causing slow performance, lag, or unresponsiveness.
Term 247
HMAC (Hash-based Message Authentication Code) is a mechanism that uses a cryptographic hash function together with a secret key to verify both the integrity and authenticity of a message.
Term 248
A host firewall is a software-based security tool that runs directly on an individual device, such as a laptop, server, or desktop, to monitor and control incoming and outgoing network traffic based on a set of security rules.
Term 249
A hosted zone is a container for DNS records that holds the information needed to route internet traffic for a domain name.
Term 250
A command-line tool in Linux that allows users to view and change the system hostname and related network identification settings without editing configuration files manually.
Term 251
Hot Standby Router Protocol (HSRP) is a Cisco-proprietary protocol that provides first-hop redundancy by allowing a backup router to automatically take over if the primary router fails.
Term 252
HSRP stands for Hot Standby Router Protocol, a Cisco proprietary protocol that allows multiple routers to work together as a single virtual router to provide default gateway redundancy.
Term 253
HTTP stands for Hypertext Transfer Protocol, the set of rules web browsers and servers use to communicate and transfer web pages over the internet.
Term 254
A network device or software that distributes incoming web traffic across multiple servers using HTTP or HTTPS protocols to ensure high availability, reliability, and performance.
Term 255
HTTPS (Hypertext Transfer Protocol Secure) is the secure version of HTTP that encrypts data between a web browser and a web server using SSL/TLS protocols.
Term 256
Hypertext Transfer Protocol (HTTP) is the foundational communication protocol used to transfer web pages and other data between a web browser and a web server over the internet.
Term 257
An IAM policy is a set of rules that determines who can access specific cloud resources and what actions they are allowed to perform.
Term 258
An IAM role is a set of permissions that an entity can assume temporarily to access cloud resources securely.
Term 259
iBGP (Internal Border Gateway Protocol) exchanges routing information between routers within the same autonomous system.
Term 260
ICMP is a network-layer protocol used by network devices to send error messages and operational information about network connectivity.
Term 261
ICMP is a network protocol used by devices to send error messages and operational information about network communication problems.
Term 262
An IDS is a security system that monitors network or system traffic for suspicious activity and alerts administrators to potential threats, but does not actively block them.
Term 263
ifconfig is a command-line tool used to configure and display network interface parameters on Unix-like operating systems.
Term 264
IGMP manages multicast group membership between hosts and routers, enabling efficient one-to-many IP communication.
Term 265
IGP (Interior Gateway Protocol) is a routing protocol used to exchange routing information within a single autonomous system, such as a corporate network.
Term 266
IKE (Internet Key Exchange) is a protocol used to set up a secure, authenticated communication channel between two parties by establishing and managing the Security Associations for IPsec.
Term 267
An image is a complete snapshot of a system's operating system, applications, and settings, used to deploy or restore computing environments quickly.
Term 268
Implicit deny is a security rule that automatically blocks any network traffic that is not explicitly allowed by an access control list or firewall rule.
Term 269
An inbound ACL is a set of rules applied to network traffic entering an interface that decides whether to allow or block that traffic based on criteria like source IP, destination port, or protocol.
Term 270
The Industrial Internet of Things (IIoT) is a network of physical devices, machines, and sensors in industrial settings that collect and exchange data over the internet to improve efficiency and safety.