Error in pin_capture.cap

Hey all,
I am stuck in this ping_capture.pcap for quite some time .All other assessments have passed .The unit testing file shows this error: Failure: Could not find ICMP request packet with the Server IP as destination.
I have simply pinged my QBox host using crio’s external ip and stored it in pcap file but still this erro arises.I have repeated this for 5 times.Can someone point out what exactly i am doing wrong?


you have to use ping on your laptop providing workspace ip as argument while keep running your vsftpd server.
start server then start tcpdump on different terminal in workspace then ping server while tcpdump is capturing packets. make sure you are writing output directly to the pcap file without using any operator (> or >>) like these.

Yes I have done the exact same thing.But still facing the issue.Can you clarify the what do you mean by ping server as i have used the following command for pinging: ping workspace_ip.
Workspace ip is the one at top right corner.

yeah, thats the right way to do so use now open pcap file in wireshark

sort using protocol like i did then check for any icmp packet if ICMP packet doesn’t exist then show me your tcpdump command. what filter are you applying or executing that command in rigth way or not.

The command i used was this:
sudo tcpdump icmp -w ./analyzing_protocol/ping_capture.pcap

an the output is :

try using sudo tcpdump -w ./analzing_protocol/ping_capture.pcap. then search icmp packets in that pcap file using wireshark. and try to filter using port number.

Well the file size has increased almost to 1 gb and the icmp packets still output the same ips.

just capture 1-2 ping packets. its enough for the output.

I have done it,result still doesnt contain
I think there is some problem with the unit testing condition

check for icmp packets. don’t worry about ip

Ok after checking for icmp files,then what should i do?


  • This is the value you provided in the file internal_ip_address_of_server

  • From this screenshot, your local ip is
    Error in pin_capture.cap

  • It could be the case this has changed since you refreshed the workspace

  • Try this, add the current local ip shown by ifconfig to the internal_ip_address_of_server, do the ping capturing step again and then try printing the tcpdump like you did in the screenshot.

Let me know if it helped :slight_smile:

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capturing 5 icmp packets and writting it into .pcap fils should suffice???

Can you please clarify what do you mean by internal_ip_address_of_server ,.And by server you mean to say the server on which the virtual machine is running or the vsftpd server.


I couldnt find anything about internal_ip_address_of_server, can you tell how can i find it?

The milestone asks you to write the internal ip address of the workspace into a file called internal_ip_address_of_server. See the bottom part of Milestone 1

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I am the dumbest person in this world.
Forgive me for my ignorance.

Thank you so muh

It can easily happen to anyone. Good luck with the next module :+1: :slight_smile:

I am using ping command on my laptop using workspace URL can I have captured packets using tcpdump command and I can see that it is captured. But I am getting the same error:- Could not find ICMP request packet. Please help.

But we were told to capture packets on the workspace itself, transfer the pcap file to our laptop and then open it in Wireshark on our laptop.