My yahoogroups has been hacked by e-mail addresses that don't show up as members. Banning members doesn't help

Question

I want to share that I ban the e-mail address and within an hour a new e-mail address sends spam. The spam filter isn't catching it, and we are getting four a day. I believe a disgruntled member who quit and joined under a different e-mail is doing this (it started the day after she quit and it has never happened before). How can they do this and post under an e-mail address not listed in the members section?

Answer 1

set-up your group so the membership has to be approved by the moderator or owner. i question each person that applies to my group via e-mail as to why they want to join.