I was having a pile of grief getting traceroute6 to work inside an Ubuntu 18.03 container (in a Ubuntu 18.03 host). Anyone venturing down this path will encounter at least these two problems.
- traceroute6 was broken for a very long time on Ubuntu, because of a bug in Debian. https://bugs.launchpad.net/ubuntu/+source/iputils/+bug/1798313 - This is now fixed, and you need to make sure you’re running iputils - 3:20161105-1ubuntu3
- There are no capabilities on the file, so once you actually get it working, you get
Operation not Permitted. The fix for that is
setcap cap_net_raw+ep /usr/bin/traceroute6.iputils
With those two fixes, you can get basic IPv6 diagnosis happening again.
I post this here to save someone else the hour or so of wasted time I went down.