> >And yes I agree - the listserver should reject nonsubscriber emails etc
>
> This has been tried and the idea abandoned. Andy Warren provided the reason
> why and it was something to due with the variable way some mail servers
> send the same return address.

Right.  For example, when I was a student at UW Madison using my class
account, email from me could have appeared as

        johnp@cat12.cs.wisc.edu   or
        johnp@cat29.cs.wisc.edu   or
        johnp@cat48.cs.wisc.edu   or anything in-between.

Personally, I would think this could be solved by requiring that anyone
posting to the list have the same username and domain name as someone on
the list (e.g. johnp@wisc.edu) and allowing people to be subscribed as
write-only (e.g. if someone has two totally different accounts and wishes
to post from both and yet doesn't want two of every messages).  Alternat-
ively (and even better) the list-server could be configured with a list of
addresses of addresses that could post even if they weren't on the list;
someone like the "johnp" account above could ask the listmanager to enable
posting from johnp@cat*.cs.wisc.edu.  Unfortunately, AFAIK the list
manager software currently in use does not have this feature and
consequently this idea--wonderful as it may be--cannot be practically
implemented.