A company we have worked with in the past has a distribution list set up with thousands of people, including one of ours.
They set the list up incorrectly and as a result, every reply to the distribution list address goes to everyone on the list, and our user's inbox is being flooded (a few emails every few minutes). However, he can’t just add it to the spam/junk filter in Outlook because every email comes from a different person, whoever replied.
Exchange has sender filtering, but I don’t know how that works when it’s a distribution list. How can I temporarily block these emails until the other company gets it fixed?