External Network Penetration Testing

What Is External Penetration Testing?

External penetration testing simulates the perspective of an attacker on the open internet, someone with no prior access who is probing your external attack surface for a way in. Our engineers conduct this test entirely from outside your network, targeting every internet-exposed asset associated with your organization.

What External Testing Covers

• All public IP addresses and associated services
• Web servers, web applications, and public portals
• VPN and remote access infrastructure
• Email and mail transfer infrastructure
• DNS configuration and zone security
• Firewall and edge device exposure
• SSL/TLS configuration and certificate validity
• OSINT: what publicly available information could assist an attacker?

Why External Testing Is a Critical Starting Point

Your external attack surface is the front door that every attacker on the internet can knock on. Most organizations that have never had a formal external test have at least one significant finding, often more.

How Often Should You Test Externally?

We recommend annual external testing at minimum, with additional testing after significant infrastructure changes, new services launched, acquisitions, cloud migrations, or changes in your IP space. Many compliance frameworks require annual external testing explicitly.

What External Testing Cannot See

External testing measures the perimeter, but most severe findings live behind it. Once an attacker gets a foothold through phishing, stolen credentials, or a single exposed service, the internal network is what determines how far the breach spreads. That is why external testing is a starting point, not a complete picture. Organizations that pair it with internal testing see both what an outsider can reach and what happens after the perimeter is crossed.

Frequently Asked Questions

What is external network penetration testing?

External network penetration testing simulates an attacker on the public internet attempting to breach your internet-facing systems, such as firewalls, VPNs, mail servers, and web services. It measures what an outsider could reach and exploit from outside your perimeter.

What does external testing cover?

External testing covers internet-facing hosts and services, looking for exposed and misconfigured services, unpatched systems, weak authentication, and leaked credentials. It is the natural starting point because it mirrors how most attacks begin.

How often should I run an external penetration test?

At least annually, and again after significant changes to internet-facing systems or a security incident. Compliance frameworks and cyber insurers commonly expect annual external testing as a baseline.