Indeed dhclient now blocks SIGTERM -- after sending it, it gets
ShdPnd: 0000000000004000
SigBlk: 0000000000004003
Downgrading to 4.3.3-5ubuntu1 fixes the bug, so the regression is not in the new upstream version nor in Debian, but in one of our recent Ubuntu changes.
Indeed dhclient now blocks SIGTERM -- after sending it, it gets
ShdPnd: 0000000000004000
SigBlk: 0000000000004003
Downgrading to 4.3.3-5ubuntu1 fixes the bug, so the regression is not in the new upstream version nor in Debian, but in one of our recent Ubuntu changes.