Anti-spam system

[Alberto Pereira <bash@ruralrj.com.br>]

People,

I have an anti-spam in my MTA system, a sendmail Sendmail 8.10.2/8.7.1.
But when somebody send a message in this format:
To: "orbs-relaytest@manawatu.co.nz"@my.host
it can pass throught my anti-spam system.
It is like this:
MAIL FROM:<spambag@fake.domain> 
RCPT TO:<victim@target@{relay}> 

Somebody knows how can i fix this bug??

Tanks so much,

Atenciosamente,
      .....
   ,,$$$$$$$$$,    Alberto Pereira  
  ;$'      '$$$$:  Analista de Suporte 
  $:         $$$$:  
   $       o_)$$$: -"E ai linux, o que faremos hoje a noite??" 
   ;$,    _/\ &&:' -"O que fazemos todas as noites link, 
     '     /( &&&    tentaremos dominar o mundo"
         \_&&&&'    
        &&&&.      -DEBIAN, THE CHOICE OF NEW GNU LINUX GENERATION!!!! 
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