This setting determines whether all submissions sent via
email should be automatically rejected. By default, this is set to allow
submissions by email. If you set this to "yes", then any email that
is sent to the list will automatically be rejected. Only postings made through
the Lyris web interface, or via a Perl script (using the Lyris/Perl toolkit)
will be allowed.
Email can fairly easily be
"spoofed", that is, someone can make the email appear to be from
someone it isn't from. Thus, email is not a very secure mechanism for
authenticating users. Someone malicious can configure their email program to be
someone else, and send messages as if they were that person.
In most mailing list situations,
users behave ethically, and do not impersonate others, so the risk of abuse is
minimal.
However, you may have a need to
have as much security as possible, so that there is very little risk of
improper email getting posted to your list. In such a case, you might want to
disallow all postings over email. Only postings through the web interface, or
postings made with a Perl script will be allowed. Note that these postings will
be subject to normal security settings, such as moderation, action phrases,
etc.