Why It Matters in Securing Your Network 

Not all network traffic is the same. Depending on where it’s headed and where it came from, network traffic can behave differently and pose different security challenges. Some threats come from the outside or involve sensitive data being exfiltrated out of the network, which is north-south traffic. Other threats move quietly within the network itself, spreading laterally through east-west traffic. 

Network Traffic Directions 

Let’s take a look at the difference between north-south and east-west in the context of network traffic.  

North-South Traffic 

North-south traffic refers to data that travels between your internal network and external systems​. Northbound traffic is the data that leaves your network, while data entering your network is considered southbound traffic. This could be e-mails, web requests, file downloads, and other types of communications. 

For instance, when you browse a website or connect to a video conference platform, that’s north-south traffic. The same applies when a doctor accesses a cloud-based electronic prescribing system or when an IT admin downloads a software update from a vendor’s site.  

Because this traffic connects your network to the internet, it typically passes through a firewall or other perimeter defense to block attackers from breaking in and to make sure sensitive data doesn’t leak out. 

However, hackers are finding ways to sneak past these perimeter defenses by exploiting vulnerabilities in these very tools or by using stolen credentials. Even a strong firewall doesn’t guarantee that every threat will be stopped. If an attacker finds an “open door”—like an unpatched server or a convincing phishing email that tricks a user into clicking a malicious link—they can slip through the perimeter. The challenge is filtering out the malicious activity while letting normal business traffic through. 

East-West Traffic 

East-west traffic refers to data that travels within your internal network between servers, workstations, or other IP-based devices inside the perimeter. 

For example, when an employee’s laptop accesses a shared printer or connects to a file server, that’s east-west traffic. Similarly, internal chat tools exchanging messages between coworkers, or a security camera system sending footage to a server, all generate east-west traffic. With virtualization and cloud computing, internal systems communicate constantly, increasing the volume of this type of traffic. 

East-west traffic is critical to monitor because once an attacker or malware gets inside your network, these internal pathways allow them to move laterally, hopping from one machine to another to escalate access and locate sensitive data.  

The challenge is that internal traffic can look legitimate—even when it’s not. An attacker can quietly scan systems, access shared files, or infect additional hosts without raising immediate alarms. Plus, they can act fast. One report found that intruders begin spreading to other systems within just 48 minutes of the initial breach. 

How Network Detection and Response Helps Watch Both Directions 

Securing both north-south and east-west traffic isn’t just best practice—it’s essential for spotting threats no matter where they originate. Without visibility in both directions, attackers can slip in unnoticed or spread silently within your network. Network Detection and Response tools, like CYBERSPAN®, are designed to keep an eye on all traffic, with east-west traffic monitoring adding a layer of security that traditional perimeter tools lack. To do this effectively, CYBERSPAN® uses machine learning and artificial intelligence to learn what your network’s “normal” looks like and then alert on deviations. 

CYBERSPAN® monitors live network traffic anywhere it’s deployed, whether that’s on-premises or in the cloud​​. It’s a passive appliance that connects to your network (for example, by plugging into a switch’s SPAN port)​. This means it can see all north-south traffic that passes through your network’s gateways and east-west traffic between devices inside the network, as long as that traffic crosses the switch where CYBERSPAN® is attached.  

Real-Time Defense, Inside and Out 

As cyber threats grow more sophisticated and aggressive, you need a robust defense system to stay ahead of attackers. CYBERSPAN® provides real-time monitoring of your north-south and east-west network traffic.  It’s built for early detection—spotting suspicious behavior in real time so you can identify and respond to potential threats quickly, whether they’re attempted break-ins, data theft, or adversaries sneaking around your network.