On Thu, 20 Apr 1995, Winship wrote:
> On Thu, 20 Apr 1995, Dave Kinnaman wrote:
>
> > * Subscription=  Open,Confirm
> >....
> > But is there some other compelling reason why would-be subscribers should
> > normally have to say "Yes, I really mean it, please subscribe me to the
> > list?"  Does the confirmation loop serve some other, important function?
>
> The purpose is to be sure mail can get back and forth between the
> subscriber's address and the LISTSERV address.  Sometimes the subscriber
> can contact LISTSERV but LISTSERV can't contact the subscriber, which
> means they wouldn't get their mail so they shouldn't be subscribed
> from that address as everything will probably bounce.  They can then
> contact you and you can try to figure out why they never receive the
> confirmation message (happens fairly often) or go ahead and ADD them
> with the proviso they'll be deleted at the first hint of trouble
> (but then you'll have an error message to work with, which may be
> more helpful than anything you can drag out of the wannabe subscriber).
 
   I think it is also used to prevent someone from faking commands to
LISTSERV for a number of things, including, deleting everyone on a list
because of a problem with the list/list-owner....  We use it here because
we know that the 'telnet addr 25' is well known on the internet and is used
to fake mail.  I don't know if the 'elmheaders' 'From:' field can also do
this, but that would make it even easier.  This is because a 'Review list-
name' is so easy to obtain for any LISTSERV list....and with that you have
a list of all subscribers.  It is not necessary to do a 'Validate= Yes,
Confirm'...but it is safer.  Again, using it is up to you.  I have found that
once subscribers understand why it is in place, they appreciate the effort
of the Listowner to make the list safer.  This can often be made clear
in a 'Welcome Message' to new subscribers.
 
--Trish