OCI 1Z0-1124-25 glossary of VCNs, subnets, routing, DRG connectivity, and hybrid design terms.
On this page
Use this glossary to clean up high-confusion OCI networking terms before you go back into mixed sets. On this exam, vocabulary mistakes usually hide a path, filter, or boundary mistake.
High-value terms
Term
What it means here
Why it matters on the exam
DNS
name-resolution layer used to map names to destinations
DNS is a common tie-break in troubleshooting order
DRG
OCI’s private-routing hub for network attachments
DRG often anchors hybrid and multi-network questions
East-west traffic
internal traffic moving between private services or tiers
this is different from internet-edge exposure
FastConnect
dedicated private connectivity between OCI and external networks
common tie-break against VPN
Internet gateway
VCN attachment that provides a path to the public internet
it answers public-path questions, not all connectivity questions
Load balancer
service that distributes incoming traffic across targets
often confused with lower-layer NLB choices
Network firewall
inspection and policy-enforcement layer for network traffic
this is about inspection and control, not just next-hop routing
NLB
Network Load Balancer with lower-layer traffic distribution behavior
not the same fit as the classic load balancer
Route table
rule set that decides where subnet traffic goes next
a route does not permit traffic by itself
VCN
OCI’s private network boundary
many questions hinge on what belongs inside this boundary
Common confusion pairs
Pair
Clean separation
Internet gateway vs FastConnect
internet gateway exposes a public path, FastConnect provides private dedicated connectivity
Load balancer vs network load balancer
the classic load balancer and NLB distribute traffic differently and fit different layers
Routing vs filtering
routing decides where traffic goes, filtering decides which traffic is allowed
DNS decision vs route-table decision
DNS resolves names, route tables determine packet next-hop behavior
Public edge vs east-west path
public edge handles ingress or egress exposure, east-west paths connect internal tiers
NAT gateway vs service gateway
NAT handles outbound internet for private subnets, service gateway reaches Oracle services privately
DRG vs gateway-at-the-edge
DRG is a private-routing hub, edge gateways serve more specific boundary crossings
Fast recall anchors
If you see…
Think…
next hop
route table or gateway
allow or deny
NSG or security list
private hybrid reachability
DRG, VPN, or FastConnect
name mismatch or wrong endpoint
DNS
If three terms blur together
Terms
Short reset
route table, NSG, security list
route table chooses path, NSGs and security lists permit or deny traffic
internet gateway, NAT gateway, service gateway
internet gateway is public edge, NAT is private-subnet outbound internet, service gateway is private access to Oracle services
DRG, VPN, FastConnect
DRG is the private hub, VPN and FastConnect are path types that attach into broader connectivity design
load balancer, NLB, network firewall
load balancers distribute traffic, network firewall inspects and enforces policy