rewolff
commented
2 months ago ??? means that the router/host at this position in the list has not responded (yet?).
So it is quite normal to see ??? at say hops 3, 4 and 5. It is then likely that the carrier that is transporting your packets configured their routers not to cooperate with mtr and similar tools. This violates internet standards, but nothing we can do about it.
As you say, seeing ??? at the end of a trace is also quite normal. mtr probed to that depth and a bit beyond that (iIRC, 5 hops), and got no response at all from any of those probes.
This makes it likely that this "last" hop is indeed your destination that happens to be configured not to respond to MTRs prodding. By default mtr sends out ICMP ECHO REQUEST packets, just like "ping" . So try ping <yourdestination" and I expect that you'll see it doesn't respond.
Worst case, it DOES respond, and then there are 5 or more routers that did not respond. Then there is a commandline option to increase the "allowable gap of not-reponding routers".
Just discovered your tool and trying to figure it out and I didn't see anything in the man page about this (unless I missed it) but what does seeing three, question marks at the bottom of the screen indicate?
If I do mtr google.com, at the bottom of the page, I see a final destination address and 0% loss. If I do mtr microsoft.com, at the bottom I see '??? and 100 loss'.