NAT & Egress
Outbound-only connectivity, its per-gigabyte cost and its zone binding.
4 to work through
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intermediate Multiple choice
A batch job's networking costs are three times its compute cost. It reads several terabytes from object storage. What is happening?
2 min answer -
intermediate
An observability platform's cloud bill shows an unexpectedly large data-processing charge from NAT gateways. What is happening, and what are the architectural fixes?
2 min answer -
advanced Multiple choice
A platform running thousands of concurrent isolated sessions starts seeing intermittent connection failures to external sites. Ports are available and CPU is low. What is the likely cause?
2 min answer -
advanced
A service intermittently times out connecting to a managed database. The database is healthy, nothing changed, and failures correlate with traffic volume. Where do you look?
1 min answer
4 terms in this topic
Invisible Resource Exhaustion
A class of failure where a shared finite resource outside the application's view is exhausted, producing intermittent unexplained errors while every …
toolNAT Gateways
The component that lets private instances reach the internet, and one of the most reliably surprising line items on a cloud bill.
conceptPort Exhaustion
Running out of available source ports for outbound connections through a NAT device, causing new connections to fail while everything appears healthy.
conceptSource NAT
Rewriting the source address of outbound packets so that many private addresses share one public address, with a translation table mapping replies back.
Neighbouring topics
Networking
General material on the network path underneath an architecture.
TCP/IP
Handshakes, congestion control, head-of-line blocking and connection reuse.
HTTP/1.1, HTTP/2 & HTTP/3
Multiplexing, prioritisation and the transport each is built on.
DNS
Resolution, TTL behaviour, traffic steering and failover latency.
TLS & Certificates
Encryption, integrity, authentication, termination points and expiry.
Layer 4 vs Layer 7
Connection-level versus request-level balancing, and what each unlocks.
Reverse Proxies
One place for TLS, routing, caching, compression and rate limiting.
Content Delivery Networks
Edge caching, origin offload, spike absorption and dynamic content.
Firewalls & Security Groups
Default-deny, stateful rules, and restricting egress as well as ingress.
VPC Design
Address planning, peering and the ranges you can never resize.
Subnetting
Tiering, zone binding, and sizing for an address-hungry platform.
Routing & BGP
How traffic finds you, anycast, and route withdrawal as a failure mode.
Service Mesh Networking
Sidecar proxies supplying mTLS, retries and traffic policy.
WebSockets & Realtime
Persistent bidirectional connections and the capacity model they impose.
gRPC Transport
HTTP/2 multiplexing, binary encoding and streaming semantics.
API Gateways
The single entry point, and the business logic that must stay out of it.
Network Performance
Latency floors, bandwidth-delay product, and what no code change fixes.
Private Connectivity
Private endpoints, peering and dedicated links to managed services.
Network Troubleshooting
Flow logs, packet paths, and localising a problem to a hop.