ADMIN: *All* mails with attachments are rejected from this list

There have been quite a lot of virus mails forwarded on the nettle and
lsh lists the last weeks. I apologize for this. The lysator mail
system, including the list server, is run by volunteers only. The
installed virus filter seems to be out of order.

For the time being, I have therefore configured these mailing lists to
accept *only* text/plain messages with no attachments. As an
sideeffect, not even attachments of type text/plain are accepted.

I hope this helps stop the virus flood for now, and that it doesn't
cause any inconvenience for proper list traffic. As usual, comments or
advice on the list administration should be sent to me, not to the
list.

Best regards,
/Niels