[Mailman-Users] Too much spam = how to hide a list?

[oli at chaoszwerg.de]

Hi,

since i installed mailman 2.1.9 i get a lot of spam on my list. how  
can i configure the list that it is not visible for people which are  
not on list?

And how can i configure a list in this way, when a message is received  
from outside the list, it will be automatically deletet?

I real have search through the internet and alot of FAQ and cant find  
a answer!

Thanks
Oli