This article explains how a message or email can appear to have been sent by a member when the email address was actually forged (spoofed) to appear that way. This will also help if a group member or owner has received spam from a group.

If your group received a message that appeared to be from a group member -- but contained spam content -- it's likely that a spammer forged the email headers of one of your group members. This tactic, known as email spoofing, is commonly used by spammers to confuse the recipient as to the true origins of the email. Unfortunately, there is no industry-wide technical solution to this problem, and Yahoo! Groups is not always able to prevent email spoofers from posing as group members.

If you are worried about spoofing in your own groups, you can prevent it by choosing to moderate messages from all members (including yourself and other moderators!). Moderating all members is a two-step process:

1. Set the group to moderate messages by default:
   • Click Management in the left navigation bar.
   • Click Messages under "Group Settings."
   • Click Edit next to "Postings and Archives."
   • In the "Moderation" section, choose Moderated and click Save Changes.
2. Make sure no members of the group are set to unmoderated (if they are, this individual setting will override the group default setting). The easiest way to check to see if any members are unmoderated is to:
   • Click Members in the left navigation bar.
   • Click Export in the upper right of the page.
   • Scroll through the Export page that is generated to see if anyone is set to "Unmoderated" (the other options are "Moderated", "Normal", and "Can't Post").
   • If any members are set to "Unmoderated," you will then need to manually change their posting settings. You can do so by:
     • Going back to the Members Page
     • Find the member whose setting needs to be changed.
     • Click the Edit Membership link (or pencil icon) next to their name.
     • Near the bottom of the page, click Edit next to the "Posting Messages" setting.
     • Select any of the settings other than unmoderated and click Save Changes.