NETWORK ANALYSIS USING WIRESHARK COOKBOOK PDF

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Introduction. Using Wireshark's features for telephony and multimedia analysis Wireshark has long become the market standard for network analysis, and with the growth of the Internet durchcomppumalchi.cf Capture. This book will be a massive ally in troubleshooting your network using Wireshark, the world's most popular analyzer. Over practical recipes provide a focus. U S I N G WIRESHARK T O S O L V E R E A L - W O R L D Practical packet analysis: using Wireshark to solve real-world network problems / Chris Sanders.


Network Analysis Using Wireshark Cookbook Pdf

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Network Analysis Using Wireshark Cookbook Yoram Orzach Chapter No. 13 " Troubleshooting Bandwidth and Delay Problems" In this package, you will find: A . The Official Wireshark Certified Network Analystâ„¢ Study Guide Distributed worldwide for Chappell University through Protocol Analysis Institute, Inc. document (PDF) from durchcomppumalchi.cf and use the search feature to look for. Network Analysis Using Wireshark Cookbook [Yoram Orzach] on durchcomppumalchi.cf * FREE* shipping on qualifying offers. This book will be a massive ally in.

We will learn how to configure the basic parameters, the start window, the time values, and the coloring rules; and most importantly, we will learn how to use the Preferences window. Chapter 2, Using Capture Filters, explains how to use capture filters which are used in order to define what data will be captured.

This chapter explains how to configure these filters and how to use them in order to capture only the desired data. Chapter 3, Using Display Filters, explains how to configure display filters which are used in order to display only the desired data, after the data is captured.

This chapter explains how to configure these filters and how they can assist us in network troubleshooting.

Chapter 4, Using Basic Statistics Tools, explains how to work with the basic Wireshark statistical features, starting from the simple tables that provides us with "who is talking" information, conversations and HTTP statistics, and others.

Chapter 5, Using Advanced Statistics Tools, explains how to work with the advanced Wireshark statistical features, including the IO graphs and TCP stream graphs that provides us with powerful capabilities for network and application performance analysis. Chapter 6, Using the Expert Infos Window, explains how to work with the Expert system, which is a powerful tool that pinpoints various types of events, such as TCP retransmissions, zero-window, low TTL and routing loops, out-of-order segments, and other events that might influence the behavior of our network.

It provides recipes for allocation of TCP performance problems, such as retransmission, duplicate ACKs, sliding-window problems such as window-full and zero-window, resets, and other related issues.

In this chapter, we will see how they work and what can go wrong in these protocols. We will see how they are affected by network problems and how we can solve network-related problems in these applications. Chapter 13, Troubleshooting Bandwidth and Delay Problems, provides recipes for finding problems caused by low-bandwidth, high-delay, and high-jitter networks. The chapter explains the behavior of TCP over high-delay, high-jitter networks, and what we can do in order to improve this behavior.

This chapter provides recipes for finding various attack patterns and what causes them.

Network Analysis using Wireshark 2 Cookbook, 2nd Edition

Appendix, Links, Tools, and Reading, provides references to some useful links from which you can get further information about Wireshark: learning sources, additional software, and so on. While there are applications that require high bandwidth, there are other applications that are more sensitive to delay and jitter.

Packet loss can influence all types of applications, but there are applications that are more sensitive to it and some that are less. In this chapter we will learn how to measure these parameters, how to check for network problems caused by it, and how to solve them when possible.

The first thing of course is to verify the communication line with the service provider.

Check whether it is a symmetric or an asymmetric line, and if it is asymmetric, check what the bandwidth is in both directions. To check the bandwidth on a communication line, follow these steps: 1. Ask for the following details: 1. Ask the SP what the line bandwidth is.

Network Analysis Using Wireshark Cookbook Book

If it is a line to the Internet, in addition to the preceding step ask the ISP what is the bandwidth to the Internet. Locate a server, a PC, or a laptop on the remote location. When using a PC or laptop for the test, don't forget that the PC itself should be strong enough to generate the traffic. A standard Windows 7 is able to generate around Mbps per TCP connection, and when opening several connections, you can get into other limitations such as disk performance and so on.

Therefore, it is recommended to try the transfer first on a LAN, where there are no bandwidth limits practically , and only then to test the SP or the ISP lines.

The best way of course is to use test equipment, if it's available. A file big enough should load the line for a significant amount of time, that is, a minute or more.

In the following illustration, you can see two local networks connected via a Service Provider SP line.

The site on the left is connected to the Internet through a firewall. Don't forget that Wireshark has its own limitations when working with high bandwidth lines.

In this case, you can configure it to use multiples files. Personally, I prefer to use other tools Omnipeek, for example when monitoring lines of Mbps and higher.

Following are the steps to measure network bandwidth with IPerf: 1. Install Iperf on both ends of the connection.

Configure one side as a client, and the other side as a server. When downloading or uploading a file, do it with a single large file and not a directory of multiple files. When transferring many small-sized files, it will take time to open and transfer each one of them, so the test will not give good results. When getting less bandwidth than expected, perform the following steps: 1. If you test the line with file copy, and in the IO graphs see sawtooth, there might be errors on the line.

To check switch or router port statistics, you can use console or telnet to connect to it and use the switch or router commands for example, show interface commands in Cisco. If you see a degradation of 80 to 90 percent of what you had expected for example, you test a line of Mbps and get 10 to 20 Mbps ; in most of the cases, it is a duplex-mismatch problem.

As shown in the How it works It isn't common, but it can also be that your service provider has a configuration problem. Check it with them. If none of the preceding cases are true, it can be that this is the reason. How it works Most of the cases in which a duplex mismatch problem occurs is when you connect using Ethernet on one side with Mbps full duplex, and the other side configured to auto-negotiate. When you configure both sides to auto-negotiation numbered 4 in the preceding diagram , it will also be fine, and will be automatically set to 1 Gbps in the case of gigabit adapters.

In this case, when one side is set to HD and the other to FD, many packets will be lost, and you will experience significant degradation in performance numbered 2 and 3 in the preceding diagram.

There's more When we download a line at a certain bandwidth, it can be that we'll get a little bit more or less of what we've bought. On the other hand if, for example, we use site-to-site VPN over the Internet, and the line is 10 Mbps, even if we have a very good Internet connection for example, when the two ends are connected to the same ISP , the encryption mechanisms of the VPN itself can take 5 to 10 percent of the line, and when measuring it, you will get somewhere between 9. In this case, for example, when you transfer a file over the line, you will see that the line is loaded with 10 Mbps that is, the bandwidth , while what is left for the file copy is usually between 9.

Measuring bandwidth and throughput per user and per application over a network connection In many cases, we need to know not only the total bandwidth of a connection, communication line or on a server port , but also who exactly are the consumers, that is from which IP addresses and port numbers the traffic is coming.

In this recipe, we will see how to measure it.

[PDF] Network Analysis Using Wireshark 2 Cookbook Practical recipes to analyze a

In order to see this, you can use proprietary tools that collect the data from the switch RMON1, RMON2, sFlow or router Cisco Netflow or Juniper Jflow , or to use Wireshark with port mirror to the communication link, and this is what we'll learn in this recipe.

Getting ready For using Wireshark to get traffic distribution, connect a laptop with a port mirror to the link you wish to monitor and start packet capture. You can also use the Tshark command from the CLI. From the Statistics menu, choose Conversations. In the Conversations window, you see the statistics on the total number of packets captured until now.

From the Statistics menu, select IO Graphs. With Wireshark, like we learned in Chapter 1, Introducing Wireshark, we capture data and analyze it.

Do this, use Wireshark, and you will get results. The purpose of this book is to try and get you there. Have fun!

We will learn how to configure the basic parameters, the start window, the time values, and the coloring rules; and most importantly, we will learn how to use the Preferences window. Chapter 2, Using Capture Filters, explains how to use capture filters which are used in order to define what data will be captured.

This chapter explains how to configure these filters and how to use them in order to capture only the desired data. Chapter 3, Using Display Filters, explains how to configure display filters which are used in order to display only the desired data, after the data is captured. This chapter explains how to configure these filters and how they can assist us in network troubleshooting. Chapter 4, Using Basic Statistics Tools, explains how to work with the basic Wireshark statistical features, starting from the simple tables that provides us with "who is talking" information, conversations and HTTP statistics, and others.

Chapter 5, Using Advanced Statistics Tools, explains how to work with the advanced Wireshark statistical features, including the IO graphs and TCP stream graphs that provides us with powerful capabilities for network and application performance analysis. Chapter 6, Using the Expert Infos Window, explains how to work with the Expert system, which is a powerful tool that pinpoints various types of events, such as TCP retransmissions, zero-window, low TTL and routing loops, out-of-order segments, and other events that might influence the behavior of our network.

It provides recipes for allocation of TCP performance problems, such as retransmission, duplicate ACKs, sliding-window problems such as window-full and zero-window, resets, and other related issues. In this chapter, we will see how they work and what can go wrong in these protocols.

We will see how they are affected by network problems and how we can solve network-related problems in these applications. Chapter 13, Troubleshooting Bandwidth and Delay Problems, provides recipes for finding problems caused by low-bandwidth, high-delay, and high-jitter networks.

The chapter explains the behavior of TCP over high-delay, high-jitter networks, and what we can do in order to improve this behavior. This chapter provides recipes for finding various attack patterns and what causes them. Appendix, Links, Tools, and Reading, provides references to some useful links from which you can get further information about Wireshark: While there are applications that require high bandwidth, there are other applications that are more sensitive to delay and jitter.

Packet loss can influence all types of applications, but there are applications that are more sensitive to it and some that are less. In this chapter we will learn how to measure these parameters, how to check for network problems caused by it, and how to solve them when possible.

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The first thing of course is to verify the communication line with the service provider. Check whether it is a symmetric or an asymmetric line, and if it is asymmetric, check what the bandwidth is in both directions.

Getting ready There are two cases that you might need to test: To check the bandwidth on a communication line, follow these steps: Ask for the following details: Ask the SP what the line bandwidth is.

If it is a line to the Internet, in addition to the preceding step ask the ISP what is the bandwidth to the Internet. Locate a server, a PC, or a laptop on the remote location. When using a PC or laptop for the test, don't forget that the PC itself should be strong enough to generate the traffic.

A standard Windows 7 is able to generate around Mbps per TCP connection, and when opening several connections, you can get into other limitations such as disk performance and so on.

Therefore, it is recommended to try the transfer first on a LAN, where there are no bandwidth limits practically , and only then to test the SP or the ISP lines. The best way of course is to use test equipment, if it's available. A file big enough should load the line for a significant amount of time, that is, a minute or more.

In the following illustration, you can see two local networks connected via a Service Provider SP line. The site on the left is connected to the Internet through a firewall. Don't forget that Wireshark has its own limitations when working with high bandwidth lines. In this case, you can configure it to use multiples files.

Personally, I prefer to use other tools Omnipeek, for example when monitoring lines of Mbps and higher. When testing your enterprise network, you can use software tools such as Iperf http: Following are the steps to measure network bandwidth with IPerf: Install Iperf on both ends of the connection.

Configure one side as a client, and the other side as a server. When downloading or uploading a file, do it with a single large file and not a directory of multiple files. When transferring many small-sized files, it will take time to open and transfer each one of them, so the test will not give good results.

When getting less bandwidth than expected, perform the following steps: If you test the line with file copy, and in the IO graphs see sawtooth, there might be errors on the line.

To check switch or router port statistics, you can use console or telnet to connect to it and use the switch or router commands for example, show interface commands in Cisco. If you see a degradation of 80 to 90 percent of what you had expected for example, you test a line of Mbps and get 10 to 20 Mbps ; in most of the cases, it is a duplex-mismatch problem.

As shown in the How it works It isn't common, but it can also be that your service provider has a configuration problem. Check it with them. If none of the preceding cases are true, it can be that this is the reason. How it works First, there are two different definitions; it is important to distinguish between: This is the effective application bytes per second that is transferred between the two ends of a connection To check the bandwidth of a communication line, you can ask the service provider for the line details, or you can simply transfer some traffic over it, use Wireshark or SNMP tool, and see what you get.

Most of the cases in which a duplex mismatch problem occurs is when you connect using Ethernet on one side with Mbps full duplex, and the other side configured to auto-negotiate. OK, X: Mismatch As you see in the diagram, when you connect a device a router in this example to a switch, when both sides are manually configured, for example, to Mbps Full Duplex FDX , the intended configuration will take place numbered 1 in the preceding diagram.

When you configure both sides to auto-negotiation numbered 4 in the preceding diagram , it will also be fine, and will be automatically set to 1 Gbps in the case of gigabit adapters. In this case, when one side is set to HD and the other to FD, many packets will be lost, and you will experience significant degradation in performance numbered 2 and 3 in the preceding diagram. There's more When we download a line at a certain bandwidth, it can be that we'll get a little bit more or less of what we've bought.

On the other hand if, for example, we use site-to-site VPN over the Internet, and the line is 10 Mbps, even if we have a very good Internet connection for example, when the two ends are connected to the same ISP , the encryption mechanisms of the VPN itself can take 5 to 10 percent of the line, and when measuring it, you will get somewhere between 9.

In this case, for example, when you transfer a file over the line, you will see that the line is loaded with 10 Mbps that is, the bandwidth , while what is left for the file copy is usually between 9. Measuring bandwidth and throughput per user and per application over a network connection In many cases, we need to know not only the total bandwidth of a connection, communication line or on a server port , but also who exactly are the consumers, that is from which IP addresses and port numbers the traffic is coming.

In this recipe, we will see how to measure it. In order to see this, you can use proprietary tools that collect the data from the switch RMON1, RMON2, sFlow or router Cisco Netflow or Juniper Jflow , or to use Wireshark with port mirror to the communication link, and this is what we'll learn in this recipe.

Getting ready For using Wireshark to get traffic distribution, connect a laptop with a port mirror to the link you wish to monitor and start packet capture. You can also use the Tshark command from the CLI. For basic statistics on users and applications that are using the communications link, perform the following steps: From the Statistics menu, choose Conversations. In the Conversations window, you see the statistics on the total number of packets captured until now.

From the Statistics menu, select IO Graphs. With Wireshark, like we learned in Chapter 1, Introducing Wireshark, we capture data and analyze it. In Netflow, Jflow, and applications that collect data from the router, the router periodically sends the collected data to the management console that analyzes it.

Cisco Netflow: For switch monitoring: For monitoring jitter and delay on a communication line, you can use simple or graphical Ping tools that will show you the line characteristics. Wireshark on the other hand does not measure the end-to-end delay but the influence that it has on the network traffic, that is inter-frame delay and how it influences applications.In this chapter, we will see how they work and what can go wrong in these protocols.

In the graph numbered 6 in the preceding diagram , you see the time between frames in milliseconds.

Network Analysis Using Wireshark Cookbook Book

When downloading or uploading a file, do it with a single large file and not a directory of multiple files. If you test the line with file copy, and in the IO graphs see sawtooth, there might be errors on the line. It is usually referred to as RTT. A standard Windows 7 is able to generate around Mbps per TCP connection, and when opening several connections, you can get into other limitations such as disk performance and so on.

Network analysis is the process of isolating these problems and fixing them, and Wireshark has long been the most popular network analyzer for achieving this goal.

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