This shows you the differences between two versions of the page.
Both sides previous revision Previous revision | Last revision Both sides next revision | ||
howto:pcap [2010/10/22 19:45] mcb30 |
howto:pcap [2010/10/22 20:09] mcb30 |
||
---|---|---|---|
Line 5: | Line 5: | ||
===== How to capture ===== | ===== How to capture ===== | ||
- | The easiest tool to use is [[http://www.wireshark.org/|Wireshark]]. This is included with most Linux distributions (just use your normal software installation mechanism to download and install a package named ''wireshark''), and can be [[http://www.wireshark.org/download.html|downloaded]] for Windows and Mac OS X. | + | The easiest way to capture a packet trace is to use [[http://www.wireshark.org/|Wireshark]]. This is included with most Linux distributions (just use your normal software installation mechanism to download and install a package named ''wireshark''), and can be [[http://www.wireshark.org/download.html|downloaded]] for Windows and Mac OS X. |
Start up Wireshark and start capturing on the appropriate network interface: | Start up Wireshark and start capturing on the appropriate network interface: | ||
Line 52: | Line 52: | ||
eth1 | eth1 | ||
+ | You can now intercept all network traffic to and from iPXE by running Wireshark on the interceptor machine and capturing on the interface ''br0''. | ||
+ | ==== Interceptor machine running Windows ==== | ||
+ | |||
+ | Under Windows, you can bridge the two network interfaces using the Network Connections control panel. Select the two interfaces, right-click, and choose ''Bridge Connections'': | ||
+ | |||
+ | {{ :screenshots:windows_bridging.png?693x298 |Bridging in Windows}} | ||
+ | |||
+ | You can now intercept all network traffic to and from iPXE by running Wireshark on the interceptor machine and capturing on the interface called ''Microsoft MAC Bridge Virtual NIC''. | ||
+ | |||
+ | ==== Intercepting a virtualised iPXE ==== | ||
+ | |||
+ | If you are running iPXE inside a virtual machine, then you can intercept all network traffic to and from iPXE by running Wireshark on the host machine, without needing to set up a separate interceptor machine. | ||
+ | |||
+ | ==== Capturing without intercepton ==== | ||
If you are unable to intercept network traffic, then you should run Wireshark on the machine that handles the functionality that you are trying to troubleshoot. For example, if the problem is that iPXE is failing to acquire an address from your DHCP server, then you should install and run Wireshark on your DHCP server. If the problem is that iPXE is successfully acquiring an address from DHCP but is then failing to boot from your iSCSI target, then you should install and run Wireshark on your iSCSI target. It may not always be practical to install Wireshark on the relevant machine. | If you are unable to intercept network traffic, then you should run Wireshark on the machine that handles the functionality that you are trying to troubleshoot. For example, if the problem is that iPXE is failing to acquire an address from your DHCP server, then you should install and run Wireshark on your DHCP server. If the problem is that iPXE is successfully acquiring an address from DHCP but is then failing to boot from your iSCSI target, then you should install and run Wireshark on your iSCSI target. It may not always be practical to install Wireshark on the relevant machine. |