Segmentation stops an attacker in one part of the network from reaching everything else. Separating user devices, servers, management networks and operational technology limits how far an attack spreads.
The short version
Start with what already exists. Most organisations have routines, documents or tools that cover part of the need, and connecting them is faster than building something new.
A quick check
- Separate management interfaces from user networks
- Restrict traffic between segments to what is needed
- Isolate OT and production systems
Making it stick
Segmentation can be introduced in steps, starting with the most critical systems. Review the result after three months and adjust. What works in practice is worth more than what looks complete on paper.