Netzwerksegmentierung als Sicherheitsaspekt

Yannick Haymann
January 11, 2023
5 min read
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We deal intensively with IT architecture and how a clean architecture can significantly increase in security without a great deal of effort.

Today, I would like to discuss two well-known but rarely used technologies from the network area: VLANs and port security.

VLAN (Virtual Local Area Network) and port security are two crucial network segmentation components that improve network security and efficiency. VLANs logically separate a physical network into different broadcast domains, providing better network organization and resource utilization. On the other hand, port security restricts unauthorized access to a network by limiting the number of MAC addresses allowed on a switch port.

VLANs offer several benefits to a network. By separating different departments, applications, or user groups into separate broadcast domains, VLANs improve network performance and reduce the risk of broadcast storms. Furthermore, VLANs provide a higher level of security, as they limit the visibility of sensitive data and reduce the risk of unauthorized access.

In addition, VLANs can be selectively routed together on a port and IP basis by internal firewalls. This is done by configuring firewall rules that allow or block traffic between different VLANs based on specific criteria such as IP address or port number. Also, using an internal firewall, an organization can control traffic flow between VLANs and ensure that only authorized traffic may pass through. For example, a company may want to allow all traffic between the VLANs for the finance and HR departments but block all traffic between the VLAN for the research and development department and the rest of the network.

Port security is a valuable tool for improving network security. By limiting the number of MAC addresses allowed on a switch port, port security can prevent unauthorized devices from accessing the network, reducing the risk of network attacks and the spread of malware or other malicious software.

In conclusion, the use of VLANs and port security can greatly enhance network security and efficiency. By logically separating a network into different broadcast domains and restricting unauthorized access, these technologies can help organizations protect their networks against potential threats. Using internal firewalls to selectively route VLANs together on a port and IP basis further enhances network security by providing the ability to control the flow of traffic between VLANs.

When designing VLANs, I find it particularly important that the grouping is not necessarily based on technical issues, but rather that you consider which systems belong together from an operational perspective and where building in "firewalls" makes sense. The question is, where can I close the bulkheads and still maintain a certain level of productivity in business areas not affected? If I simply separate the "server network" from the "client network", I have largely interrupted all business processes. For example, if I isolate the warehouse management components (for example, database, application server and controllers) from the network in a suspected case, I have contained the restriction to the logistics area, at least for now.