Internal users

[Brad Ralph]

Hi everyone,

I am having trouble understanding how Internal Users work.  I have just set up 
Kolab 2.1 RC1 using the default instructions and created some internal users.  
I want them to be able to send and receive email on my server / domain but 
not to be able to send email to any other domain.  ( this is what I 
understood the Internal User type would do). 

However, If I send an email from an unrelated external webmail account, the 
email gets through to the internal users mailbox.  Similarly I can send email 
to an external address from this account.

Either I must be doing something wrong or I misunderstood what an internal 
users was.

Can anyone suggest how to create an account that only sends and receives 
emails internally on my domain, but does not allow any external access at 
all. 

Regards,
Brad Ralph