At the list level,

 

Filter= Also,[log in to unmask]

 

You should use “Also” in order not to override the site-level filter, unless you have a specific reason to do otherwise.

 

If this person is spamming multiple lists, the LISTSERV postmaster might wish to use the “SERVE [log in to unmask] OUT DROP” command to simply drop anything he sends to the server on the floor without a response.  But that’s a server-level command that a list owner can’t issue, so you’d have to get in touch with whoever runs the server to do that.

 

Nathan