In this episode of PING, Dr Rolf Winter (https://blog.apnic.net/author/rolf-winters/), the Professor of Data Communications at Augsburg University of Applied Sciences (https://www.hs-augsburg.de/en/) discusses his work on ‘reverse traceroute’, which is an approach to using the well-known traceroute (https://en.wikipedia.org/wiki/Traceroute) mechanism but driven from the other end.The inherent problem with traceroute and its related diagnostics is that it only informs you about the path outwards from your address to the other end.Reverse traceroute is an attempt to ‘mechanize’ the reverse path information, using proposed new codepoints in the Internet Control Message Protocol (ICMP). Rolf discusses this approach and some of the logistical issues with attempting to modify an established protocol like ICMP, and measurements of the acceptability of proposed new codepoints in the wild.Read more about Professor Winter’s work on the APNIC Blog:* Troubleshooting ‘the other half’ (https://blog.apnic.net/2023/03/01/troubleshooting-the-other-half/)* Watch his presentation at DENOG 14 (https://www.youtube.com/watch?v=Y7NtqLEtgjU)* Visit his GitHub code repository (https://github.com/HSAnet/reverse-traceroute/)