Term 151
Direct Attach Copper
Direct Attach Copper is a type of high-speed copper cable used to connect networking equipment over short distances without needing separate transceivers.
Acronym study
Terms 151–180 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 151
Direct Attach Copper is a type of high-speed copper cable used to connect networking equipment over short distances without needing separate transceivers.
Term 152
AWS Direct Connect is a cloud service that lets you create a dedicated private network link from your on-premises data center to AWS, bypassing the public internet for more consistent and secure connectivity.
Term 153
Direct-attached Storage (DAS) is a storage device connected directly to a computer or server without going through a network.
Term 154
A DLL error is a message that appears when a Windows program cannot find or properly use a Dynamic Link Library file it needs to run.
Term 155
dmesg is a Linux command that displays messages from the kernel ring buffer, used to diagnose hardware and boot issues.
Term 156
A DMZ (demilitarized zone) is a network segment that sits between an internal private network and the public internet, hosting publicly accessible services while keeping the internal network isolated.
Term 157
DNS is the system that translates human-friendly domain names like example.com into machine-readable IP addresses so computers can find each other on a network.
Term 158
A DNS log is a record of all Domain Name System queries and responses that pass through a server, providing a trail of which domains were requested, by whom, and when.
Term 159
DNS poisoning is a cyberattack that corrupts a DNS resolver's cache with false information, redirecting users to malicious websites without their knowledge.
Term 160
A DNS record is a set of instructions stored on a DNS server that tells clients how to interact with a domain, most commonly by mapping a human-readable domain name to an IP address.
Term 161
A DNS zone is a distinct part of the global Domain Name System (DNS) namespace that is delegated to a specific administrator or organization for management, containing resource records for a domain.
Term 162
The Domain Name System (DNS) is the internet's phonebook that translates human-friendly domain names like google.com into computer-friendly IP addresses like 172.217.0.46.
Term 163
A cyberattack that floods a target with traffic or requests to exhaust its resources, making it unavailable to legitimate users.
Term 164
Dot1Q is the industry-standard networking protocol that tags Ethernet frames with a VLAN identifier, allowing multiple virtual LANs to share the same physical network link.
Term 165
Driver rollback is a Windows tool that reverts a device driver to its previous version to fix problems caused by a recent driver update.
Term 166
An OSPF router that lost the DR/BDR election on a multi-access segment.
Term 167
DSCP (Differentiated Services Code Point) is a 6-bit field in an IP packet header used to classify and prioritize network traffic for Quality of Service (QoS).
Term 168
DSL (Digital Subscriber Line) is a technology that uses existing telephone lines to provide high-speed internet access without interrupting your phone service.
Term 169
Dynamic Trunking Protocol (DTP) is a Cisco proprietary protocol used to automatically negotiate whether a switch port should operate in access mode or trunk mode.
Term 170
A duplex mismatch occurs when two connected network devices are configured with different duplex settings (one half-duplex, one full-duplex), leading to poor performance and data errors.
Term 171
Dynamic ARP Inspection is a security feature that validates ARP packets on a network to prevent man-in-the-middle attacks by ensuring that only legitimate ARP messages are forwarded.
Term 172
Dynamic auto is a switchport trunking mode where the port will automatically form a trunk if it receives a trunk negotiation request from the other device, but will not actively initiate trunking.
Term 173
A Cisco proprietary switchport mode that makes a port actively request to form a trunk but also allow the port to become a trunk if the connected device requests it.
Term 174
DHCP is a network protocol that automatically assigns IP addresses and other configuration settings to devices so they can communicate on a network.
Term 175
Dynamic NAT is a method of mapping multiple private IP addresses to a pool of public IP addresses automatically, allowing many devices to share a limited number of public addresses.
Term 176
A route that is automatically learned and updated by a router using a routing protocol, rather than being manually configured.
Term 177
EAP is a flexible authentication framework used in network access control, supporting multiple methods like passwords, certificates, and tokens.
Term 178
ECC (Elliptic Curve Cryptography) is a public-key cryptographic method that uses the mathematics of elliptic curves to provide strong security with smaller key sizes than older methods like RSA.
Term 179
EIGRP is an advanced distance-vector routing protocol that uses bandwidth and delay by default to find the best path for data packets across a computer network.
Term 180
An Elastic IP is a static, public IPv4 address that you can allocate to your cloud account and remap to different resources, masking failures by allowing quick reassignment.