umask

[koen de wijs]

Hello,
I have a question aboout the umask under FreeBSD. I couldn't find what 
it exactly is.
It is something for setting files how you set the 'xrwxrwxrw'
I found a file where you could chance it but don't knwo anymore what it 
was.

I want to use this for my ftp-server with FreeBSD.
I have a directory 'upload' where all my friends can put there files. 
They are all members of the group 'ftpusers'. But when they put a file 
in that directory all the other users from the group 'ftpusers' 
canchange or delete this file. I want to change it so that the write bit 
for the group is off when someonse of the ftpusers group writes 
something in the folder 'upload'. Can I do this with changing the umaks 
and how do I change that? I couldn't found any information on that.

Thanks ,
Koen