ok thanks for info.

 i'm using spamhalter and it define the most of them as spam.

Hi,

 its able to check if the useraccount exist before anybody can send to an other local user ? because i have set a rule so that mail accept from localhost with a default-user or system-user account from my forum, message-system etc. but mercury accept mails from not-existing local users. how i can change this ? so it require a existing user with password before it can send anything.

[quote user="Heini_net"]

Hi,

 its able to check if the useraccount exist before anybody can send to an other local user ? because i have set a rule so that mail accept from localhost with a default-user or system-user account from my forum, message-system etc. but mercury accept mails from not-existing local users. how i can change this ? so it require a existing user with password before it can send anything.

[/quote]

Not sure what you mean here but if receiving mail via MercuryS you can tell it not to receive nail for non-local users.
You need to uncheck "Accept mail for invalid local addresses" 
 

I'm sure that i have unchecked the "Accept mail for invalid local adresses" option.. i dont know why i get Messages from invalod local adresses... but i check it again today evening, when i'm at home.

[quote user="Heini_net"]I'm sure that i have unchecked the "Accept mail for invalid local adresses" option.. i dont know why i get Messages from invalod local adresses... but i check it again today evening, when i'm at home.[/quote]

You are always going to get mail FROM invalid email addresses, including your own.   This is typical of spammers.  THere is no way to block on the From: address except via filtering and that's more trouble than it's worth.