On Mon, 1 Dec 2003 14:27:52 -0500, Samuel Neff <[log in to unmask]> wrote:

>I'm looking into ListServ Lite for some private customer support mailing
>lists but am very concerned about the whole loop checking thing.  According
>to the FAQ, Docs, and posts here ListServ will by default reject any message
>that has "From:" in it as a whole word.  The FAQ says this can't be turned
>off but the docs say it can.

LISTSERV is not rejecting on the word "From:".  It is rejecting on the
_address_ of the server found in any one or more of "Sender:", "From:", or
"Reply-To:" fields.  For example:

The enclosed  message, found in  the TBI-WORKING  mailbox and shown  under the
spool ID 11429 in  the system log, has been identified  as a possible delivery
error notice for the following reason: "Sender:", "From:" or "Reply-To:" field
pointing to the list has been found in mail body.
-----
...
>Sender: "WORKING and brain injury" <[log in to unmask]>
>Reply-To: "WORKING and brain injury" <[log in to unmask]>
>From: "Robert Demichelis" <[log in to unmask]>
>To: "WORKING and brain injury" <[log in to unmask]>
>Subject: RE: [TBIWORK]
...

>The docs say Loop checking can be turned off only in the Pro version.

LISTSERV Classic version is the correct terminology.

>So, a few questions..
>
>1.  Is that right?  We can't turn it off at all in Lite?

Correct.
See:  http://www.lsoft.com/products/default.asp?item=featurecomp

>2.  What's really wrong with turning off loop checking in a _private_ list
>anyways?  In a private list, only e-mail sent to the list from a registered
>subscriber is sent to the list.  If an e-mail comes in from a
>non-subscriber, ListServ won't forward it.

What about forged From: addresses?  Either by malicious persons or by any of
the various e-mail viruses that "borrow" addresses from user's address books.

What about (external) mail loops, where a legitmate piece of mail goes out to
some subscriber with a 'broken' mail server (MS POP3 "connector" is very bad
at doing this) that "reflects" the message back to the list without changing
any message headers?  As far as LISTSERV knows it is a message with the
correct To: and From: addresses and (unless loop checking catches it) will be
endlessly repeated through the list, making everyone very unhappy very
quickly.