[Mailman-Users] Restricted Posting Not Working

[Frederic Herman]

I am using vs 2.0.13.  I have set the privacy option: Restrict posting 
privilege to list members? (/member_posting_only/) to yes.

However, some spam is still getting through from  non-member senders.  I 
have examined the headers, and don't see how the posts are getting 
through to the held-for approval phase.

What should I be looking for?

TIA

Fred