Lesson 4: Ports, Protocols, and Services
Week of Tue, Oct 6 · lesson closes Mon, Oct 12
Take Meerk's quiz for Lesson 4
This lesson's items
Exact due times are in Canvas.
Watch — Professor Messer
Watch — Professor Messer: Ports and Protocols (N10-009)
Free, independent educational resource. Not affiliated with or endorsed by CompTIA. Watch, then read the notes below.
Know these cold
- Well-known ports (0–1023): FTP=20/21, SSH=22, Telnet=23, SMTP=25, DNS=53, HTTP=80, POP3=110, IMAP=143, HTTPS=443, LDAP=389, RDP=3389, SNMP=161.
- TCP (reliable): 3-way handshake (SYN → SYN-ACK → ACK). Connection-oriented. UDP (fast): no handshake. Connectionless.
- DHCP process (DORA): Discover (broadcast) → Offer (server) → Request (client confirms) → Acknowledge (server confirms).
Meerk's quiz — open the Lesson 4 gate
10 questions, no time limit. 85% on your first attempt in a 24-hour window opens the gate. Retakes inside the window are practice — they help you learn, they don't count. Work alone; the point is to know it, not to have seen it.
Dinner Table Question
Ask at home: Why do web browsers default to port 443 today instead of port 80?
En español: ¿Por qué los navegadores web usan por defecto el puerto 443 en lugar del puerto 80 hoy en día?