I've worked with IT generalists who could set up any software product in the market but couldn't tell you why a flat network causes problems, or what a trunk port does. That gap shows up at exactly the wrong moment — usually when something breaks and a client is watching.

You don't need to be a network engineer. But you should be able to:

Read a basic network diagram
Understand the difference between a switch, a router, and a firewall. Know where each device sits in the topology and what traffic flows through it. If a client shows you their network diagram, you should be able to ask intelligent questions.

Understand VLANs
Virtual LANs are how modern networks segment traffic — separating guest Wi-Fi from corporate systems, for example. You don't need to configure them from scratch, but you should know what they are and why they matter for security and performance.

Know the basics of DHCP and DNS
Most connectivity problems trace back to one of these two services. If a device 'can't connect', you should know how to check whether it has an IP address, and whether it can resolve a hostname.

Understand subnets (just enough)
You don't need to subnet a /19 in your head. But knowing that 192.168.1.0/24 gives you 254 usable hosts, and that two devices on different subnets need a router to talk, is foundational.

These aren't deep skills. A week of focused study — CompTIA Network+ material is a good starting point — gives you enough to be useful in any infrastructure conversation and to spot the difference between a configuration problem and a hardware failure.