Data Ingress vs. Egress in the Cloud
Understanding the concepts of egress and ingress in cloud security is critical for managing network traffic. While these terms just mean “exit” and “entrance” in general, in network security, they are separate and essential areas that network teams focus on for data security and traffic management.
Defining Egress vs. Ingress
What is Egress?
Egress (“exit”) refers to the flow of data moving out of a private network into the public internet or another external network. Monitoring and filtering egress traffic is very important in network operations, especially in cloud environments, where controlling the movement of data helps organizations maintain security, for example to protect against unauthorized exfiltration.
What is Ingress?
Ingress (“entrance”) refers to the flow of data into a private network from an external source, typically the public internet. In cloud computing, managing ingress traffic means keeping threat actors, malware, unauthorized users, and any other unwanted visitors out of your network.
The Difference Between Ingress and Egress
Ingress refers to data traffic entering a network boundary, while egress refers to data traffic leaving it. Together, they define how data flows into and out of cloud environments, shaping security controls, routing decisions, monitoring, and cloud cost management.
| Ingress | Egress |
Direction | Into the network | Out of the network |
What it covers | Incoming data traffic | Outgoing data traffic |
Typical examples | User requests, API calls, service-to-service calls | Responses, data exports, external service calls |
Security focus | Access control, authentication, filtering | Data protection, exfiltration prevention |
Cost considerations | Usually lower or none | Often metered and billable in cloud environments |
Common controls | Firewalls, load balancers, ingress controllers | NAT gateways, egress firewalls, encryption policies |
Primary risks | Unauthorized access, DDoS attacks, API abuse | Data exfiltration, compliance violations, unexpected cloud spend |
Best practices | Enforce identity-based access, use WAFs, apply rate limiting, log and monitor all inbound traffic | Restrict outbound destinations, encrypt data in motion, apply least-privilege egress policies, continuously monitor egress flows |
Ingress and Egress in the Cloud
Egress from Cloud Environments
In cloud environments, egress traffic involves data transmission from a controlled, internal network space—for example, a data center or cloud infrastructure—to the wider internet. This movement requires careful handling, particularly through network address translation (NAT), to ensure secure and authorized data transmission. Firewalls are also critical in monitoring and allowing this outbound traffic, particularly in response to internal requests or established network sessions. See the picture below for reference.
Egress:
Ingress into Cloud Environments
In cloud environments, ingress involves external traffic attempting to access the private network. This can include unsolicited external data packets and requests that are not responses to internal actions. Firewalls are essential in these scenarios because they block or scrutinize incoming traffic, using security policies and configurations are in place to only allow certain types of ingress traffic into the network. See the picture below for reference.
Ingress:
Explore four cloud egress traffic risks you need to know about.
