Term 451
Perfect forward secrecy
Perfect forward secrecy is a property of secure communication protocols that ensures that even if a long-term private key is compromised, past session keys and the messages they encrypted remain safe from decryption.
Acronym study
Terms 451–480 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 451
Perfect forward secrecy is a property of secure communication protocols that ensures that even if a long-term private key is compromised, past session keys and the messages they encrypted remain safe from decryption.
Term 452
Persistent Disk is a durable, high-performance block storage service for Google Cloud virtual machines that retains data even after the VM is shut down or deleted.
Term 453
A Personal Area Network (PAN) is a small network that connects devices within a person's immediate workspace, typically within a range of about 10 meters.
Term 454
Ping is a network utility used to test whether a remote computer or device is reachable across an IP network and to measure the round-trip time of data packets.
Term 455
A pipe is a mechanism that connects the output of one command directly to the input of another command, allowing data to flow between processes in a chain.
Term 456
A PMKID attack is a wireless network attack that exploits a vulnerability in the RSN IE (Robust Security Network Information Element) of Wi-Fi Protected Access (WPA/WPA2) networks to recover the Pre-Shared Key (PSK) without needing to capture the full four-way handshake.
Term 457
A point-to-point link is a direct communication connection between two devices or network nodes that allows them to exchange data without passing through any other intermediate device.
Term 458
Point-to-point OSPF is a network configuration where Open Shortest Path First routing protocol operates over a direct link between exactly two routers, treating the link as a simple connection without the need for a designated router or backup designated router.
Term 459
A networking protocol that creates a secure tunnel for data to travel between two points over the internet, often used for VPNs.
Term 460
A DNS pointer record (PTR) maps an IP address to a domain name, performing the reverse of a standard A or AAAA record.
Term 461
Traffic policing is a network mechanism that monitors data traffic against a configured rate limit and drops or remarks packets that exceed that limit to enforce bandwidth usage.
Term 462
Pop-up ads are unsolicited browser windows or overlays that appear automatically while browsing, often used for advertising or, maliciously, to spread malware.
Term 463
POP3 (Post Office Protocol version 3) is an email protocol that downloads messages from a mail server to a single device and then typically deletes them from the server.
Term 464
A networking technique that maps multiple private IP addresses and their ports to a single public IP address using unique port numbers.
Term 465
A port channel is a technology that groups multiple physical network links into a single logical link to increase bandwidth and provide redundancy.
Term 466
Port forwarding is a network technique that directs incoming traffic from the internet to a specific device or service inside a private local network.
Term 467
Port mirroring is a network monitoring technique that sends a copy of all packets seen on one switch port (or VLAN) to another port for analysis.
Term 468
A port number is a 16-bit number used in networking to identify a specific application or service on a device in a network communication.
Term 469
Port security is a network switch feature that restricts which devices can connect to a port based on the device's MAC address, preventing unauthorized access.
Term 470
PortFast is a Cisco switch feature that immediately brings a port into the forwarding state, bypassing the normal Spanning Tree Protocol (STP) listening and learning phases, so that devices connected to that port can start communicating right away.
Term 471
Post Office Protocol (POP) is a standard internet protocol used by email clients to retrieve email from a remote server and download it to the user's local device.
Term 472
Post-quantum cryptography refers to cryptographic algorithms designed to resist the computational power of future quantum computers, which could break current public-key systems.
Term 473
A Power Distribution Unit (PDU) is a device that distributes electrical power to multiple pieces of IT equipment, such as servers, switches, and routers, in a data center or server room.
Term 474
Power over Ethernet (PoE) is a technology that allows electrical power and data to be transmitted over a single Ethernet cable to devices like IP cameras, wireless access points, and VoIP phones.
Term 475
A secret password or passphrase that two devices share beforehand to prove they are allowed to connect and communicate securely.
Term 476
Precision Time Protocol is a network protocol used to synchronize clocks across devices with extremely high accuracy, often within microseconds or nanoseconds.
Term 477
A prefix length is the number of bits in a subnet mask that identifies the network portion of an IP address, written after a slash (e.g., /24).
Term 478
A private DNS zone is a hosted DNS namespace that is only resolvable from within specific virtual networks or private environments, not from the public internet.
Term 479
A private endpoint is a network interface that securely connects a service over a private IP address inside a virtual network, keeping traffic off the public internet.
Term 480
Private Google Access lets virtual machines in a Google Cloud VPC reach Google APIs and services using private IP addresses, without needing public internet access.