TCP/IP Network Traffic Analysis with Wireshark ( nettraffanalyswireshark | 35 hours )

1. Familiarity with ISO OSI Reference Model - ITU-T X.200 and TCP/IP protocol stack.

2. Basic knowledge of Unix/Linux OS: UNIX terminal, directory structure, listing files and directo-
ries, making directories, changing to a different directory, copying, moving and removing files and directories, redirection, pipes, processes - listing suspended and background processes.

Hardware & Software
1. HW: min 16GB of RAM, min 60GB free disk space available.
2. OS: Ubuntu Linux OS is preferred. In this case the following applications should be installed: ip,
iperf, ipcalc.
3. SW: Wireshark application (https://www.wireshark.org/download.html).

All should be in latest stable, available releases.

Wireshark is a free open source packet analyzer used for troubleshooting network issues. Network packet analysis is a technique used to view, in real time, the raw data sent and received over a network interface. This is useful for troubleshooting network configuration and network application problems.

In this instructor-led, live training (onsite or remote), participants will learn advanced techniques for troubleshooting the functionality and performance of a network and its applications. This course is an extension of "Network Troubleshooting with Wireshark", which focuses primarily on common HTTP applications. In this training, we consider protocols and connection mediums such as Wi-Fi, HTTPS, SMTP, enterprise applications and more.

By the end of this training, participants will be able to:

• Isolate and solve network security issues using the Wireshark CLI
• Troubleshoot applications that use protocols beyond HTTP, including HTTPS, FTP, mail, DNS, etc.
• Troubleshoot network connection problems in enterprise applications such as databases, RPC, etc.
• Troubleshoot connection problems in media applications such as VoIP and streaming
• Use network forensics to trace and detect security issues

Audience

• Network engineers
• Network and computer technicians

Format of the Course

• Part lecture, part discussion, exercises and heavy hands-on practice

Day 1

Network analysis overview

1. OSI reference model and TCP/IP networks essentials.
2. Troubleshooting tools, methodologies.
3. Introduction to Wireshark
4. What is Wireshark? Portable Wireshark. Resources.
5. Wireshark GUI structure: Panes (Packet List, Details, Packet Bytes), Status Bar, ... .
6. Architecture and processing flow. What and why cannot be seen with Wireshark?
7. Supported protocols. Dissectors.
8. Preferences and configurations; global and profile specific.
9. Time values.
10. Lab exercises.

Day 2

Capture traffic

1. Things to consider before start.
2. Promiscuous mode.
3. Capture filters.
4. Automatic stop criteria.
5. Remote capture.
6. Lab exercises.

Traffic analysis: tools and approaches

1. Analysis checklist.
2. Using features: name resolution, colorization, marking, ignoring, commenting, using time references, time shifts, etc.
3. Understanding Expert System.
4. Accessing options through Right-Click functionality.
5. Interpretation (reference patterns), OS/driver Offload features impact.
6. Saving results.
7. Lab exercises and case studies.

Day 3

Traffic analysis: tools and approaches (cont.)

1. Filtering traffic: Display filters (preparing "in-flight" filters, macros), following stream.
2. Quantitative analysis.
   1. Basic predefined descriptive statistics and summaries: Capture Properties, Protocol Hierarchy, Conversations, Endpoints, Packets Lengths, IP-specific.
   2. Protocol specific analysis (e.g.: TCP Stream Graphs).
   3. Advanced custom statistics with I/O Graph.
   4. Flow visualization.

Day 4

Traffic analysis: protocols

1. Data-Link Layer: Ethernet II.
2. Network Layer: IPv4.
3. Transport Layer: TCP, UDP.
   1. Packet loss and recovery.
   2. Previous segment lost and Out-of-Order Segments events.
   3. Duplicate ACKs and Fast Retransmissions.
   4. TCP Retransmissions.
   5. Zero Window, Window changes and other window problems.
4. Application layer: HTTP, FTP.
5. Lab exercises and case studies.

Day 5

Traffic analysis: common issues in network performance assessment

1. Cause of performance problems.
2. Packet loss.
3. Bandwidth issues. Layered approach to measurement.
4. Latency: assessing end to end latency, visualization.
5. Lab exercises.
6. (Wireshark) command-line tools:
   1. tshark (terminal-based wireshark) / dumpcap / rawshark, tcpdump
   2. editcap, mergecap, capinfos, text2pcap.

Advanced topics

1. Advanced filters, grouped iostats.
2. Summary and Q&A.