Hi Shlomo, 1. Send me the code and I will try to test it. 2. Are you sure there is a reply when your message reaches the destination? And does it depend on the destination? Some destinations may disable it for security reasons (DDOS attacks).
Uri. אורי u...@speedy.net On Sun, May 19, 2024 at 5:43 PM Shlomo Solomon <shlomo.solo...@gmail.com> wrote: > I teach computer networking and the latest assignment I gave my > students was to use Python and Scapy to emmulate traceroute. The code > is simple: > - send an ICMP packet with TTL = 1 which will fail but return the > first hop address > - continue sending ICMP packets - each time increasing the TTL to get > the next hop > - if the ICMP reply is NOT an error, we have arrived. > > None of my student submissions worked, which was strange, so I tried my > own code which I know is correct. > It also did not work. > The error messages arrive for each hop, but it seems that the NO ERROR > message (when the destination is reached) is not arriving. > I also checked with Wireshark and see error replies (as I should) for each > hop, but then (when I assume I have reached the destination) there is > no reply. > > I then tried disconnecting my computer from my ISP and connected via a > Hotspot on my phone - PROBLEM SOLVED. > > So this seems to be a problem with my ISP (019) blocking some traffic. > But I don't know what the next step is. > If I call customer service, I'm sure no-one will understand what I want. > > BTW - ping and the "real" traceroute work fine. > I also looked at router settings, but did not find anything suspicious. > > Can anyone suggest how to explain my problem to my ISP? > > ALSO - if there is anyone using 019, I would be happy to send my code > for testing to verify that this is really a problem with 019. > > > > -- > Shlomo Solomon > http://the-solomons.net > Claws Mail 4.0.0 - KDE Plasma 5.24.7 - Kubuntu 22.04 > _______________________________________________ > Linux-il mailing list -- linux-il@cs.huji.ac.il > To unsubscribe send an email to linux-il-le...@cs.huji.ac.il >
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