Networking

What this domain actually tests

A preview of Network+, at a much shallower depth. You need recognition and basic configuration, not subnetting mastery.

Common ports are the core of it, and they are pure recall — which makes them free marks:

Port	Protocol		Port	Protocol
20/21	FTP		143	IMAP
22	SSH		443	HTTPS
23	Telnet		445	SMB
25	SMTP		3389	RDP
53	DNS		137–139	NetBIOS
67/68	DHCP		161	SNMP
80	HTTP		389	LDAP
110	POP3		427	SLP

Know TCP versus UDP for each. DNS and DHCP use UDP; anything needing reliable ordered delivery uses TCP.

The traps

Wi-Fi bands and the trade-off

This is the most commonly misremembered part of the domain, and the logic is simple once stated:

• 2.4 GHz — travels further, penetrates walls better, but is slower and more congested (only three non-overlapping channels: 1, 6, 11).
• 5 GHz — faster, more channels, less interference, but shorter range and worse through walls.
• 6 GHz (Wi-Fi 6E) — fastest, least congested, shortest range.

The exam gives you a scenario — "users at the far end of the building have a weak signal" — and expects you to reason with the trade-off. Longer range means 2.4 GHz. Higher speed means 5 GHz.

Know the standards too: 802.11n (both bands), 802.11ac (5 GHz only), 802.11ax / Wi-Fi 6 (both, faster, better in crowds).

DHCP and DNS at a concept level

DHCP hands out IP addresses automatically. DNS resolves names to IP addresses. A machine with a 169.254.x.x address (APIPA) failed to reach a DHCP server — that is a diagnostic gift, and it appears.

If a user can reach a site by IP address but not by name, it is DNS. That symptom-to-cause mapping is examined.

SOHO router configuration

Port forwarding, DHCP reservations, SSID and wireless security (WPA2 versus WPA3 — always pick the newer), changing default credentials, and firmware updates. Basic, practical, and directly asked.

How to study it

Drill the port list as flashcards in both directions — "what port is RDP?" and "what runs on 3389?" — because performance-based questions make you match protocols to numbers and partial credit is not guaranteed.

Then log into a home router and actually look at the settings. Set up port forwarding. Change the wireless security mode. Twenty minutes of this makes the SOHO questions concrete.

At 20% this domain is worth roughly eighteen questions, and a large share of them are pure recall. It also builds the foundation for Network+ later, so time spent here pays twice.