Networking, Protocols & Wireless
22 practice questions with explanations — 15 free to try
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PassNova has 22 GIAC GSEC (Security Essentials) practice questions on Networking, Protocols & Wireless, each with a clear explanation. A 15-question taster is free with no sign-up; the full bank is part of PassNova Premium. Updated for 2026.
Networking, Protocols & Wireless: example questions & answers
2 worked examples with answers and explanations below. Try 15 GIAC GSEC (Security Essentials) questions free in the browser; the full 22-question Networking, Protocols & Wireless bank is part of PassNova Premium.
A client opens a TCP connection to a web server. Which sequence of flags completes the three-way handshake before any application data is sent?
- AACK, then SYN, then SYN/ACK
- BSYN, then ACK, then FIN/ACK
- CSYN/ACK, then SYN, then PSH
- DSYN, then SYN/ACK, then ACK✓
Answer: The client sends a SYN carrying its initial sequence number, the server answers with SYN/ACK (its own SYN plus an acknowledgement of the client's), and the client's final ACK completes the handshake. FIN is used to close a connection rather than open one, and the server never sends the first segment of a connection the client initiates.
An analyst runs tcpdump on a workstation and sees this exchange: 10.0.0.5.51514 > 10.0.0.20.8443: Flags [S], seq 1234567, win 64240 10.0.0.20.8443 > 10.0.0.5.51514: Flags [R.], seq 0, ack 1234568, win 0 What does the reply from 10.0.0.20 most likely indicate?
- AThe host is reachable but no service listens on 8443✓
- BThe server is throttling the client with a zero window
- CThe service accepted the connection and awaits data
- DA firewall silently dropped the SYN before it arrived
Answer: Flags [R.] is a RST with the ACK bit set. A host that receives a SYN for a port with no listening socket answers with RST/ACK, so the machine is up but nothing is bound to 8443 (nmap would call the port closed). A silent drop would produce no reply at all, and an accepted connection would return SYN/ACK, which tcpdump shows as Flags [S.]. The zero window simply accompanies the reset.