Firewalls and Next-Generation Firewalls
The first line of defense — and what modern firewalls actually do.
Key takeaways
- Traditional firewalls filter by port/protocol; NGFWs add application awareness and deep packet inspection.
- Stateful firewalls track connection state, allowing return traffic for established sessions.
- Defense-in-depth means firewalls are one layer, not the only layer.
- Egress filtering is as important as ingress — it stops C2 callbacks and data exfiltration.
The firewall is often called the "front door" of network security — but a modern NGFW is really more like a trained security guard with a database of known threats, application signatures, and behavioral baselines.
Knowledge check
Why is egress filtering important even if your perimeter firewall blocks all inbound threats?
Who does this for real
The services where Vijilan runs this work for partners and their clients.