Keith Bromley
Sr. Manager, Product Marketing at Ixia

What Is Inline Security?

December 13, 2019 by Keith Bromley

People talk about inline security a lot. But what is it? I thought I would take a moment to explain. There’s also an in-depth explanation here – Ixia’s Inline Security Architecture.

Businesses are finding themselves fighting security battles on many fronts that include:

  • an increase in the velocity and variety of cyberattacks
  • an increase in the number of alerts that they need to investigate
  • malware camouflaged in encrypted traffic
  • and breaches that are harder than ever to spot

Each of these threats can have a significant impact on the bottom line.

To reduce the impact of security threats, a proactive cyber defense is necessary. A real-time, proactive defense helps reduce the onslaught of attacks and attack vectors against the network. Note, this does not eliminate the need for a reactive defense to perform in-depth analysis of potential security threats.

Inline security solutions are one of the ways that enterprises can deploy high impact security solutions to address these security threats in real-time and near real-time. Inline means that all production traffic must pass through the device, like a firewall or intrusion prevention system (IPS), before it can continue on into the network. An “inline solution” is more than just adding an inline security appliance though. Those devices require complete data visibility, which allows examination of all suspect network traffic.

Therefore, a good implementation of an inline solution consists of an external bypass switch, a network packet broker, and the security appliances. This is illustrated in the following generic diagram.


This combination of equipment enables security teams to deploy the following use cases to address network security concerns:

  • Increase network reliability with better fail-over techniques.
  • Improve security appliance survivability.
  • Perform SSL decryption to expose hidden security threats.
  • Reduce security architecture complexity.
  • Deploy measures to capture indicators of compromise (IOC).

For more information, check out the following in-depth technical brief on inline security – Ixia’s Inline Security Architecture.