Port Numbers Worth Memorizing for Network+ (and Which Ones You Can Skip)

Port number memorization is the most painful part of Network+ study because everyone treats it as binary — either you know all 100+ assigned ports or you fail. That’s a study trap. The N10-009 exam draws port questions from a focused list of about 40 ports, and 20 of those carry most of the weight.

This post is the prioritized list — must-memorize cold, nice-to-know, safely-skip — based on what shows up on actual exam attempts. Save yourself 5 hours of memorizing port 2049 for NFS that’s never tested.

The tier system

Three tiers, total of about 40 ports. If you can’t recall a port instantly within tier 1, you’re not done studying. Tier 2 you should recognize on sight. Tier 3 you can let go.

Tier 1 — Must memorize cold (25 ports)

These appear in roughly 60–80% of port questions on the N10-009. Memorize port number, transport protocol (TCP/UDP), and what the protocol does. Drill until reflexive.

Pattern note: most “secure” versions of plain-text protocols just add a higher port (HTTP/80 → HTTPS/443; LDAP/389 → LDAPS/636; IMAP/143 → IMAPS/993; POP3/110 → POP3S/995). Memorize the unsecured number, then know the secured variant. That cuts the memorization in half.

Tier 2 — Recognize on sight (15 ports)

You’ll see these but they’re not high-frequency. If you can’t recall the port number from memory but you recognize it when you see “port X” in a question, you’ll get the answer right by elimination.

The database ports (1433, 1521, 3306, 5432) are often tested as a group — “which port is MySQL?” or “which port is MS SQL?” If you remember just three (1433 MSSQL, 3306 MySQL, 5432 Postgres), that covers most variations.

Tier 3 — Safely skip

If a port doesn’t appear in tier 1 or tier 2, it’s probably not on the exam in any meaningful way. Specifically you can skip:

• Anything above 6000 unless it’s 8080 or 8443
• Anything obscure: NNTP (119), Whois (43), Gopher (70), Finger (79), POP2 (109), TACACS+ (49 — yes, this is real, but rarely tested at Net+ level)
• Vendor-proprietary ports outside the database list above
• Game ports, RTP/RTCP dynamic ranges, ephemeral source ports (which use the 49152–65535 range)

Spending memorization time on these is a poor ROI. The exam draws from the well-known port set + a handful of common services. If you’ve never seen the port asked in 10 practice tests, it’s not worth the cognitive load.

The grouping trick — memorize by service family

Instead of memorizing 40 random numbers, group them by service:

Web: 80 (HTTP), 443 (HTTPS), 8080 (HTTP alt), 8443 (HTTPS alt)

Email send: 25 (SMTP), 587 (SMTP submission), 465 (SMTPS legacy)

Email receive: 110 (POP3), 995 (POP3S), 143 (IMAP), 993 (IMAPS)

File transfer: 20/21 (FTP), 22 (SFTP/SCP — via SSH), 69 (TFTP), 989/990 (FTPS), 445 (SMB)

Remote access: 22 (SSH), 23 (Telnet), 3389 (RDP), 5900 (VNC)

Directory: 389 (LDAP), 636 (LDAPS)

Name / address: 53 (DNS), 67/68 (DHCP)

Time + logs: 123 (NTP), 514 (Syslog)

Network management: 161/162 (SNMP — poll/trap)

VPN: 500/4500 (IPsec), 1701 (L2TP), 1723 (PPTP)

VoIP: 5060/5061 (SIP)

Databases: 1433 (MS SQL), 3306 (MySQL), 5432 (PostgreSQL), 1521 (Oracle)

Grouping reduces the memorization from 40 random numbers to roughly 12 themed clusters. Most people can hold 12 themes in working memory better than 40 isolated facts.

The TCP vs UDP cheat — what to do when you forget

If you can recall the port number but not whether it’s TCP or UDP, default to TCP unless one of these UDP-favoring criteria applies:

• It’s a query/response protocol where speed matters more than reliability (DNS query, SNMP, NTP)
• It’s a streaming or real-time protocol (RTP for media, VoIP RTP)
• It’s a configuration / discovery protocol (DHCP, TFTP, BOOTP)
• It’s a logging protocol that prefers throughput over delivery guarantee (Syslog)

The reasoning: TCP is the default for anything that needs reliable delivery (web pages, file transfers, email, database queries). UDP is for anything where lost packets are tolerable and speed matters.

How the exam phrases port questions

Three question patterns repeat:

Pattern 1 — Port-to-protocol lookup: “Which protocol uses port 443?” Answer: HTTPS. Simple recall, ~5 seconds.

Pattern 2 — Protocol-to-port lookup: “An administrator wants to allow secure email retrieval. Which port should be opened?” Answer: 993 (IMAPS) or 995 (POP3S) depending on context.

Pattern 3 — Scenario / troubleshooting: “A user can ping the server but cannot reach the web application. Which port should the administrator verify is open on the firewall?” Answer: usually 80 (HTTP) or 443 (HTTPS) depending on whether the question mentions encryption.

The scenario questions are the high-value ones. They combine port knowledge with troubleshooting reasoning. Practice these specifically — single-step recall is easy; combining recall with a 2–3 step troubleshooting chain is what separates passing from failing.

The 10-port quick-quiz routine

A daily 5-minute drill that builds reflexive recall. Pick 10 ports from tier 1 randomly. For each, write down: port number, protocol name, TCP/UDP, one-sentence description.

Example daily quiz:

1. Port 22  → ?
2. Port 53  → ?
3. Port 110 → ?
4. Port 443 → ?
5. Port 514 → ?
6. Port 587 → ?
7. Port 636 → ?
8. Port 993 → ?
9. Port 3389 → ?
10. Port 161 → ?

Score yourself out of 10. Anything under 9/10 means you’re not ready. Repeat daily until you’re 10/10 for 5 days running.

Beyond memorization — what to do during the exam

Three exam-day tactics specific to port questions:

1. Answer port questions first. They’re pure recall and fastest. Get the easy points banked early before tackling time-consuming scenario questions.

2. Use elimination on uncertain answers. If the question asks “which port is SFTP?” and you forgot it’s 22, eliminate any options that are clearly wrong (21 is FTP, 23 is Telnet, 25 is SMTP). You can often narrow to 1–2 options through elimination even when you don’t recall the exact number.

3. Don’t second-guess. Port answers are deterministic — there’s exactly one right answer per question. If you wrote down 443 for HTTPS, do not change it because you’re “not sure.” First instinct on port questions is usually correct because you either know it or you don’t.

What this maps to on N10-009

Port number questions appear under multiple N10-009 domains:

• 1.5 (Common Networking Services) — direct port-to-protocol questions
• 4.1 (Network Security Concepts) — firewall rule questions involving port numbers
• 5.5 (Troubleshooting Common Network Issues) — scenario questions about blocked ports

Roughly 8–12 questions in a 90-question exam will involve port numbers. That’s 10–13% of your possible score. Worth a few hours of memorization.

Where to take this next

If your subnetting is still slow, Subnetting Without a Calculator — The Magic-Number Method is the technique that gets you under 30 seconds per problem.

If you need to drill the OSI vs TCP/IP layer model that often pairs with port questions, OSI vs TCP/IP Layer Mapping — A Cheat Sheet for the N10-009 Exam is the cheat sheet.