Control of Bounced Messages

[Stephen <stephen1 @ worldnet . att . net>]

I'm getting some returned mail items with addresses that don't show up on
our list of subscribers.  If someone who was not a subscriber sent
something to the list, would that be obvious or just have more fairly
undecipherable jargon in the headers?

The number of messages is increasing so I must not be taking the correct
action, which is actually 'no' action since I'm not sure how to handle this.

Steve Cox
San Francisco