It's a common configuration to have non-member posts to a mailing list be rejected. It seems that most list servers run from /etc/aliases or similar which means that mail has already been accepted by the time the list server sees it. Once mail has been accepted (SMTP code 250) it can be sent on, discarded, or a bounce message can be sent. In the case of spam (which often accounts for most non-member mail to a list) we don't want to generate a bounce message as that hurts innocent third parties. But in the case of members who send mail from their wrong address we want to inform them. Ideally a non-member post to a mailing list would get a SMTP level rejection (SMTP code 55x). When a real person sent the mail they get a bounce message and can re-send if appropriate, if a spam bot sent the mail then it gets discarded. http://postfwd.org/ What's the best way of getting it to work that way? I'm idly considering writing a script to take the list of members from Mailman and automatically generating a Postfwd configuration from it, the above URL describes Postfwd. One benefit of using Postfwd in that manner could be that anyone who subscribes to one list could be allowed to send mail to all lists on the same server, it doesn't have to be that way (Postfwd is configurable and generating more rules isn't difficult) but it seems like a good idea. The Mailman controls seem to only control posting access based on the membership of the list in question. -- My Main Blog http://etbe.coker.com.au/ My Documents Blog http://doc.coker.com.au/