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In Wireshark, which pane shows the decoded protocol fields for the packet you selected?

A
B
C
D
to track
2026 Statistics

Key Facts: GCIA Exam

106

Questions

GIAC

67%

Published Pass Point

GIAC

4 hours

Exam Time

GIAC

$999

Exam Fee

GIAC Pricing

120 days

Attempt Window

GIAC Delivery Policy

36 CPEs

Renewal Requirement

GIAC Renewal

GIAC GCIA is GIAC's network intrusion analysis certification built around SANS SEC503. The current published exam format is 106 questions in 4 hours with a 67% passing score and $999 exam pricing. GIAC identifies three major coverage areas: fundamentals of traffic analysis and application protocols, open-source IDS with Snort and Zeek, and network traffic forensics and monitoring. Certification attempts are open-book, proctored, and must be completed within 120 days of activation.

Sample GCIA Practice Questions

Try these sample questions to test your GCIA exam readiness. Each question includes a detailed explanation. Start the interactive quiz above for the full 200+ question experience with AI tutoring.

1In Wireshark, which pane shows the decoded protocol fields for the packet you selected?
A.Packet List
B.Packet Details
C.Packet Bytes
D.Conversations
Explanation: The Packet Details pane is where Wireshark breaks the selected frame into protocol layers and fields. It lets an analyst expand Ethernet, IP, TCP, and application-layer structures to inspect exact values. The Packet List pane is only a summary, and the Packet Bytes pane shows raw bytes rather than decoded fields.
2What is the primary benefit of using Wireshark's "Follow TCP Stream" feature?
A.It rebuilds the application conversation carried over a TCP session.
B.It automatically decrypts encrypted payloads in the capture.
C.It converts the capture into only SYN and ACK packets.
D.It removes retransmissions from the pcap file.
Explanation: Follow TCP Stream reassembles data exchanged across a TCP conversation so an analyst can read the application content in order. This is useful for reviewing HTTP requests, commands, or text-based protocols without manually piecing together each segment. It does not decrypt protected traffic by itself or modify the original capture.
3How does a capture filter differ from a display filter during packet analysis?
A.A capture filter hides packets after capture, while a display filter stops packets from being written.
B.A capture filter limits what is collected, while a display filter only changes what is shown afterward.
C.A capture filter works only in Wireshark, while a display filter works only in tcpdump.
D.A capture filter can match protocols, while a display filter can only match IP addresses.
Explanation: A capture filter is applied before packets are stored, so unwanted traffic is discarded at collection time. A display filter works after packets have already been captured and only affects what the analyst sees in the interface. This distinction matters on busy links because capture filters reduce storage use and packet drops.
4What traffic matches the tcpdump capture filter `tcp port 80 and host 192.0.2.20`?
A.Only packets from 192.0.2.20 to destination port 80
B.All TCP packets where either endpoint is 192.0.2.20 and either TCP port is 80
C.Only HTTP responses from 192.0.2.20
D.All traffic to or from 192.0.2.20 regardless of protocol
Explanation: In BPF syntax, `host 192.0.2.20` matches either source or destination host, and `port 80` matches either source or destination port. Combined with `tcp`, the filter captures TCP traffic where one side is 192.0.2.20 and port 80 appears on either endpoint. That means both client requests and server responses can match.
5Multi-byte numeric values in packet headers are normally transmitted in which byte order?
A.Little-endian
B.Big-endian
C.Reverse ASCII
D.Variable-length encoding
Explanation: Network byte order is big-endian, meaning the most significant byte is transmitted first. Analysts use this when interpreting raw hex values in packet captures. If you read multi-byte fields with the wrong endian assumption, header values such as ports or lengths will appear incorrect.
6Which Ethernet field tells the receiver what protocol is encapsulated in the frame payload?
A.Frame Check Sequence
B.Source MAC address
C.EtherType
D.Preamble
Explanation: The EtherType field identifies the next protocol carried inside the Ethernet frame, such as IPv4, IPv6, or ARP. Wireshark uses this value to decide which dissector to apply after the Ethernet header. Other Ethernet fields serve addressing or integrity functions rather than protocol identification.
7What does the Wireshark display filter `ip.addr == 203.0.113.10` match?
A.Only packets sourced from 203.0.113.10
B.Only packets destined for 203.0.113.10
C.Packets where 203.0.113.10 appears as either source or destination IPv4 address
D.Packets where 203.0.113.10 appears anywhere in the payload
Explanation: The `ip.addr` field is direction-agnostic and matches either source or destination IPv4 address. This is useful when you want all traffic involving a host without writing separate source and destination conditions. Matching payload bytes would require a different filter entirely.
8Why is a sufficiently large snap length important during packet capture?
A.It prevents TCP from retransmitting lost packets.
B.It avoids truncating packets so important headers and payload data are preserved.
C.It forces the NIC to validate every checksum in hardware.
D.It disables packet fragmentation on the network.
Explanation: Snap length controls how many bytes of each packet are written to the capture. If the value is too small, upper-layer headers or payload content may be cut off, which can prevent file extraction, reassembly, or protocol parsing. Analysts often use a full snap length when they need complete evidence.
9How do `frame.len` and `ip.len` normally differ in Wireshark for an Ethernet-carried IPv4 packet?
A.`frame.len` is the IP payload length, while `ip.len` is the Ethernet frame size.
B.`frame.len` includes the Layer 2 framing, while `ip.len` is the total IPv4 datagram length.
C.They are always identical because both represent the on-wire packet size.
D.`ip.len` includes Ethernet padding, while `frame.len` excludes it.
Explanation: `frame.len` refers to the full captured frame size at Layer 2, while `ip.len` is the IPv4 total length field that starts at the IP header and excludes the Ethernet header. Comparing them helps analysts understand encapsulation overhead and whether padding or truncation is present. The two values often differ by the size of the link-layer header and trailer context.
10What is the practical effect of running tcpdump with the `-nn` option?
A.It disables both hostname resolution and service-name resolution.
B.It captures only non-IP traffic.
C.It enables packet reassembly for fragmented datagrams.
D.It writes packet payloads in binary instead of text.
Explanation: The `-nn` option keeps addresses and port numbers numeric by suppressing name lookups for both hosts and services. This speeds up analysis and prevents misleading delays or extra DNS traffic caused by resolution attempts. It also makes the exact on-wire values clearer when reviewing captures.

About the GCIA Exam

GIAC GCIA validates hands-on network intrusion analysis skills. It centers on packet analysis, protocol interpretation, Snort and Zeek detection, and large-scale network forensics with flow data.

Assessment

Open-book, proctored exam with multiple-choice and CyberLive practical items

Time Limit

4 hours

Passing Score

67%

Exam Fee

$999 (GIAC (Global Information Assurance Certification))

GCIA Exam Content Outline

45%

Fundamentals of Traffic Analysis and Application Protocols

Packet dissection, TCP/IP behavior, IPv6, fragmentation, Wireshark and tcpdump filtering, and application-layer protocol analysis.

33%

Open Source IDS: Snort and Zeek

IDS architecture, rule syntax, detection tuning, Zeek logs, behavioral analysis, and common evasion considerations.

22%

Network Traffic Forensics and Monitoring

Flow-based scoping, SiLK workflows, forensic pivots from packets to flows, baselining, and incident-driven traffic analysis.

How to Pass the GCIA Exam

What You Need to Know

  • Passing score: 67%
  • Assessment: Open-book, proctored exam with multiple-choice and CyberLive practical items
  • Time limit: 4 hours
  • Exam fee: $999

Keys to Passing

  • Complete 500+ practice questions
  • Score 80%+ consistently before scheduling
  • Focus on highest-weighted sections
  • Use our AI tutor for tough concepts

GCIA Study Tips from Top Performers

1Index your notes around protocols, packet flags, Snort keywords, and Zeek logs so your open-book strategy stays fast.
2Practice reading TCP handshakes, retransmissions, resets, fragmentation, and IPv6 behavior directly in packet captures.
3Memorize the difference between capture filters and display filters because GCIA tests both workflows.
4Know what common application protocols look like on the wire, especially DNS, HTTP, TLS, SMTP, and FTP.
5Write and tune Snort rules until options like `content`, `offset`, `depth`, `distance`, `within`, and `flow` feel natural.
6Learn the highest-value Zeek logs and how to pivot across `conn.log`, `dns.log`, `http.log`, `ssl.log`, `files.log`, and `notice.log`.
7Use flow data to answer scale questions quickly: top talkers, scanning patterns, exfiltration windows, and lateral movement scope.
8Review why evasions work so you can explain both the attacker technique and the defensive control that reduces the blind spot.

Frequently Asked Questions

What is the current GCIA exam format?

As of March 2026, GIAC publishes GCIA as a 106-question exam with a 4-hour time limit and a current 67% published passing score. The exam is open-book, web-based, and proctored, and GIAC uses CyberLive hands-on items alongside traditional multiple-choice questions.

What does GCIA cover?

GIAC publicly groups GCIA into three coverage areas: traffic analysis and application protocols, open-source IDS with Snort and Zeek, and network traffic forensics and monitoring. In practice, that means you need to be comfortable reading packets, understanding protocol behavior, writing or tuning IDS logic, and using flow data to scope suspicious activity.

Is GCIA open book?

Yes. GIAC classifies GCIA as an open-book certification attempt. That does not make the exam easy because the time limit is still tight, so successful candidates usually rely on a well-organized index and strong packet-analysis fluency rather than trying to look up every answer.

How does GCIA differ from GSEC or GCIH?

GSEC is broader and more foundational across general security operations, while GCIH focuses more on attack techniques and incident handling workflow. GCIA is narrower and deeper on traffic analysis, protocol behavior, IDS technologies, and network-centric forensics.

What are the GCIA renewal requirements?

GIAC certifications remain active for 4 years. Renewal currently requires 36 CPE credits during the cycle plus the GIAC renewal fee, or you can renew by retaking the certification within the renewal window.

How should I study for GCIA?

Plan around packet analysis repetition, not memorization alone. Spend most of your study time reading traces in Wireshark, reviewing TCP and application-protocol behavior, practicing Snort and Zeek interpretation, and then using flow data to answer incident-scoping questions quickly.

What jobs value GCIA?

GCIA is especially relevant for SOC analysts, network defenders, intrusion analysts, detection engineers, and incident responders who work with packet captures, IDS telemetry, or flow data. Employers that value SANS-aligned technical depth often treat GCIA as a strong signal of practical network-analysis skill.