Internal penetration test
Testing from inside the network, simulating an attacker who has already gained a foothold.
It starts from the assumption that has become standard: someone clicked something, or a device was compromised. From there the tester pursues what a real intruder would, hunting credentials and escalating toward domain control.
It is usually where the most uncomfortable findings appear, because internal networks are built for convenience and rarely designed to contain someone who is already inside.
Where this comes up
Internal penetration test sits inside our penetration testing work. If you are trying to work out what this means for your own environment rather than in the abstract, that is the page worth reading next, and a short call will get you a straight answer faster than either.