Others have mentioned switches or hubs for gathering the packets. Network Taps are another alternative, and many are available used (ebay) for relatively small prices. https://www.ebay.com/sch/i.html?_from=R40&_trksid=p2499334.m570.l1313&_nkw=network+tap&_sacat=58058
Kurt On Wed, May 12, 2021 at 4:12 PM Ron W <ronw.m...@gmail.com> wrote: > I am trying to use WireShark to diagnose a network problem between a > Windows PC and a Linux-based controller (for a robot). > > The controller uses uboot and TFTP to download the Linux image from the > PC. Using the controller's serial port, I can see the messages output by > uboot and by Linux. The messages as as expected and the controller appears > to work correctly except after downloading Linus via TFTP, the PC > application is not able to communicate with the controller via TCP/IP. > > So, I connected an Ethernet switch between the PC and the controller and > also connected a laptop to the switch so I can monitor with WireShark. > > What I see in WireShark's capture log (see attached screen picture) would > have made sense, but the log is not showing the TFTP messages. So, to make > sure TFTP was actually working, I interrupted uboot before it started > downloading Linux. I then entered commands to have uboot download various > test files I created and inspect what was downloaded to make sure the > expected content was in the controller. As I did this, I continued to > monitor with WireShark. Still I did not see anything after the initial ARP > request from the controller, asking for the MAC corresponding to the IP > address of the PC. i did not even see an ARP reply from the PC. > > Since I'm not seeing the TFTP messages, nor the PC's ARP response, I have > to assume I configured WireShark incorrectly. Looking at my capture > selection and capture options (see attached screen pictures), I can't find > anything to explain not seeing the TFTP messages in the capture log. > > I even tried a fresh install of WireShark on another laptop that had never > had Wireshark on it. Same result: No TFTP message in the capture log. > > I have used WireShark successfully in the past. As best I can remember, I > setup WireShark the same as I have in the past. > > Still, I must be doing something wrong. Any advise on what I need to fix > in my WireShark settings? > > Thanks in advance > > ___________________________________________________________________________ > Sent via: Wireshark-users mailing list <wireshark-users@wireshark.org> > Archives: https://www.wireshark.org/lists/wireshark-users > Unsubscribe: https://www.wireshark.org/mailman/options/wireshark-users > mailto:wireshark-users-requ...@wireshark.org > ?subject=unsubscribe
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