As a penetration tester, it's quite important to determine the technologies used by a target network or organization prior to performing an external network penetration test. Discovering technologies used by a target usually proves to be very useful prior to any sort of offensive attack on the target network or organization. It allows us, as penetration testers, to better equip ourselves with the appropriate tools to get the job done efficiently and successfully. Imagine starting a new job as a carpenter but you arrive on your first day without any tools—how can you expect to be successful?
Furthermore, knowing about the technologies and security controls used on the target network beforehand will allow us to better prepare ourselves by researching and developing exploits to take advantage of known security weaknesses...