>Hello,
>
>It's possible to unsubscribe e-mail addresses without the subscriber
>authorization, simply sending an e-mail to the list with the unsubscribe
>command?
>
>It's possible to deactivate this possibility?

Validate= All,Confirm will require confirmation for all mailing list
commands, including "SIGNOFF", and should prevent the kind of abuse
you describe.

Generally I would hesitate before implementing this, as people tend
to get annoyed when the signoff process is made more complicated.
--
Jacob Haller, Technical Support, L-Soft international, Inc
  LISTSERV (R) is a registered trademark of L-Soft.
   Support is available 9:00-18:00 ET, Monday-Friday
    except on the following holidays:
     http://www.lsoft.com/products/default.asp?item=holidays