MTR is awesome, but in a recent update to the package in brew means that you need to sudo to use it. This is particularly a pain when you don’t run as an account that is able to sudo. In addition, a lot of the functionality of MTR has been moved out into the mtr-packet binary, which makes a lot of the instructions out there on how to resolve this annoyance now wrong. A quick and dirty fix to get around this is to set the SUID bit, and change ownership to root. You also need both mtr and mtr-packet in your path.