See https://bugzilla.samba.org/show_bug.cgi?id=11164, there're fixes at least for the error messages attached to that bug.
** Bug watch added: Samba Bugzilla #11164 https://bugzilla.samba.org/show_bug.cgi?id=11164 -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1357471 Title: Samba4 AD DC randomly dies, error: "Did not manage to negotiate mandetory feature SIGN for dcerpc auth_level 6". To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/samba/+bug/1357471/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
