Post upgrade from exchange 2010 we had a group that we would use and publish externally: groupA- the members of this distribution list were groupb groupc and groupd - groupA does not require that all senders are authenticated, (or in delivery managment senders inside and outside of my oranization is selected) and in exchange 2010 received emails from outside the company and they were received by the members of groupb/c/d. Since migrating to exchange 2013, when sending to group A we are getting NDR from groups b/c/d saying senders must be authenticated.
my workaround is to setup groups b/c/d to receive email from all senders, but im a bit loathe to expose all of my nested distribution lists to the outside world when this wasnt an issue in exch2010.
would anyone have any ideas on where to look on this? finding this particular query very difficult to search.