TTL is one of the most mis-understood concept in networking, I have tried to answer all the questions below about TTL. How TTL works? When exactly TTL is decremented? TTL decremented at ingress or egress? When packet is dropped? Demystifying IP TTL ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-jJFZ1_nyULk.html Demystifying IP TTL Quiz Scenario 1 Lab ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-5Fn4hdo-TmY.html Demystifying IP TTL Quiz Scenario 2 Lab ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-WDIy766_Kts.html Demystifying IP TTL Quiz Scenario 3 Lab ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-9UiTZSujjac.html If you find these videos useful, please like and share the videos and subscribe to Demystifying Networking !!
Reference Material: help.mikrotik.com/docs/display/ROS/Mangle NB!!! Do not randomly change TTL unless there is a very specific reason why you want to do it. As seen in the video haphazardly just adding a rule to change the TTL value can potentially result in connectivity issues. Only use TTL for specific use cases or if a hop count seems to exceed the default value on ROS. You are required to understand how TTL functions and how to possibly change it for the MTCRE, but I strongly encourage to leave TTL values alone as much as possible :)
Hello, I will consider doing a MikroTik switching series at a later stage or cover STP on its own. The MTCRE focuses only on the routing aspects of ROS and unfortunately does not cover STP.
Depends for the reason of the error, usually it is because the TTL gets expired because of a routing loop. So I would probably start by doing a traceroute to the destination and seeing where the traces loops and then look between those two devices if there is anything strange occurring.