What is a Firewall, and How to Get Past it?

A firewall is a critical network security device that monitors inbound and outbound traffic according to predefined security rules. Firewalls protect against malicious attacks and grant granular control over access between network segments.

In this comprehensive technology guide, we’ll explore:

• The history and evolution of firewalls
• Detailed overview explaining how firewalls work
• Capabilities and services offered by next-generation firewalls
• Statistics on the firewall market landscape
• Technical criteria for selecting the ideal firewall solution

A Brief History of Firewall Technology

Network firewall adoption traces back to the late 1980s as the internet began popularizing interconnected networks. Early firewall predecessors operated mainly as packet filters allowing or blocking traffic based on protocol, IP addresses, and ports.

First generation firewalls focused only on the network layer lacking full awareness of applications, users, and content. By the mid-90s, stateful inspection capabilities emerged tracking connection state information across packets. This enabled basic traffic analysis like identifying responses tied to requests.

Soon after, integrated security suites consolidated anti-virus, intrusion prevention, virtual private networks (VPN), and URL filtering under unified firewall platforms. Centralized management interfaces reduced complexity for administrators.

As encryption protocols like SSL/TLS proliferated in the 2000s, deep packet inspection techniques allowed next-generation firewalls to decrypt and inspect content within connections after reassembly. DPI fueled capabilities for fine-grained controls centered on users, applications, websites, and data patterns.

Fast forward to today with over 50% of enterprises relying on next-gen firewalls plus availability offered natively from major cloud providers like AWS, Azure, and Google Cloud. Gartner estimates the firewall market reaching $4.27 billion in total revenue by 2024. As threats accelerate, firewalls anchor digital security strategies.

How Do Firewalls Work?

Firewall appliances or agents sit inline across networks to analyze traffic against configured rulesets and block unauthorized communication attempts. Decryption, packet reassembly, threat identification, and filtering happen automatically at high speeds without impacting network throughput.

Common firewall deployment topologies strategically segment trusted internal networks from external locations:

Perimeter firewalls place appliances between private LANs and external networks like the internet. They focus on heavy inspection for inbound threats.

Internal firewalls sub-divide private networks to construct security zones isolating departments or infrastructure. They prevent lateral movement post-compromise.

Distributed firewalls secure remote locations, cloud environments, and roaming users via VPNs. They maintain policies regardless of access point.

Next-gen capabilities apply intelligent policies based on users, trusted devices, applications, websites, data patterns, vulnerabilities, and threat intelligence.

For example, rules may:

• Allow finance staff access to accounting applications but block social media
• Permit patching systems but deny external RDP connections
• Block malicious websites and command-and-control botnet IPs

The firewall grants authorized access while minimizing attack surface.

Key Capabilities of Next-Generation Firewalls

Modern firewalls handle increasingly complex hybrid environments via integrated suites administering network, cloud, endpoints, IoT devices, and more from unified interfaces.

Network Traffic Analysis and Access Controls

NGFWs combine IP address and port parameters with user identity, trusted device state, application fingerprints, vulnerable software, website categories, data types, and threat feeds to enable dynamic access decisions.

Priorities shift from solely targeting threats to also allowing intended business connectivity through least-privilege principles.

Controls stretch across on-premises, cloud infrastructure, applications, encryption, guest WiFi, BYOD, and web traffic workflows.

Intrusion Prevention Systems (IPS)

IPS built into NGFWs leverage attack signatures and anomaly detection to identify malignant traffic and actively block threats inline without needing separate IPS appliances.

Automated sharing of new attack signatures across vendors bolsters community protection.

VPN and Secure Remote Access

Site-to-site VPN, client VPN, zero trust network access, and identity-based secure access enable workforce mobility by extending internal security controls. Multi-factor authentication ensures authorized remote sessions.

Web application firewalls (WAF) fortify internet-facing services and APIs against exploits like SQL injection, cross-site scripting, DDoS floods, and web scraping.

Advanced Threat Protection

NGFWs utilize a variety of advanced threat protection techniques:

URL/DNS Filtering – Allow/deny website access by categories plus block malicious links

Anti-malware – Catch trojans, viruses, spyware, worms, botnets, crypto mining, and command-and-control traffic

Sandboxing – Safely test suspicious files and URLs in a virtual container to uncover malicious payloads

TLS/SSL Decryption – Decode encrypted content for inspection then re-encrypt sessions using installed certificates

Data Loss Prevention – Restrict unauthorized data sharing or exfiltration by scanning content patterns

Browser Isolation – Allow safe web browsing from IoT, POS, and dormant connections via remote browser proxies

These combinations aim to fully uncloak threats across protocols and encrypted traffic.

Firewall Market Share Statistics

Recent reports help quantify NGFW adoption trends:

• 50% of enterprises now utilize NGFWs as the center of security infrastructure (Gartner)
• 61% of organizations saw their firewall investment increase substantially (Cisco)
• 78% view firewalls as strategic to digital transformation initiatives (Palo Alto)
• NGFWs make up $2.39 billion growing around 6% yearly (Gartner)

As networks evolve to integrate cloud, branches, teleworkers and transform digitally, purpose-built firewalls remain elemental.

How to Select the Right Firewall

While SMB environments may opt for unified threat management (UTM) all-in-one security appliances, large enterprises generally deploy specialized best-of-breed firewall infrastructure.

Follow this systematic process when evaluating solutions:

1. Set Technical Requirements

• Traffic volume / bandwidth needs
• Latency thresholds
• Number of locations and form factor
• Network topology and integration
• Hybrid cloud alignments
• Inspection depth needs
• Reporting expectations

2. Detail Selection Criteria

• URL filtering / DNS security
• IDS / IPS
• TLS decryption
• Sandboxing
• BYOD / guest access
• Endpoint integration
• Management interface
• Reliability ratings
• Training and support options

3. Research Vendors

• Gartner Magic Quadrant ratings
• NSS Labs comparative testing
• Peer reviews highlighting pros/cons

4. Shortlist Options

• Cisco Firepower NGFW
• Palo Alto Networks
• Fortinet FortiGate
• Check Point Quantum Security Gateway
• Juniper SRX Series
• Sophos XG Firewall

5. Review and Demo Contenders

• Fine-tune requirements to specific models
• Validate capacity, features, logging, TCO
• Assess reporting, analytics, response workflows

6. Select Best Fit

Consider both technology strengths and vendor partnership dynamics. while accounting for refresh cycles and future expansion.

Conclusion

Next-generation firewalls offer the first line of active defense monitoring inbound and outbound traffic to counter modern threats in highly dynamic network environments.

Core firewall strengths focus on threat prevention plus implementing least-privilege access controls between users, devices, applications, websites, cloud services, and on-premises infrastructure.

Advanced protections and centralized policy orchestration simplify administration while providing detailed audit trails.

Moving forward, firewall intelligence and automation assists understaffed security teams grapple with sophisticated attacks across complex hybrid digital ecosystems.
Integrating complementary safeguards like endpoint detection, penetration testing, backups, patching and user education forms a resilient security posture optimized for digital progress.