About the mappings

Hi,all,would you tell me how to config the mappings file so that i can reject some certain mail hosts for example abc@yzx.com to deliver mails to my iplanet messaging server 5.1?
[200 byte] By [705066] at [2007-11-25 9:08:17]
# 1
try..SEND_ACCESS*tcp_*|*@badhost.baddomain.com|*|*$NDisabled$ because$ of$ problem$ messages
Rockit2069 at 2007-7-1 16:09:18 > top of Java-index,E-Mail, Calendar, & Collaboration,Sun Java System Messaging Server...
# 2
The mail host i would like to reject is a outside host,and i must add a FROM_ACCESS column to achieve this?
705066 at 2007-7-1 16:09:18 > top of Java-index,E-Mail, Calendar, & Collaboration,Sun Java System Messaging Server...