When you filter on IP addresses you can not filter on the received headers, only headers that are added to the message during its delivery to your mail server, such as the Originating_IP: header. If that header exist you can filter on it using the Header item.
If you are trying to reject all mail from an IP address and you are collecting mail via SMTP you should use the Firewall feature (version 7 or below) or the IP Access feature (version 8 or higher) to block IP addresses.
If you are collecting mail using a Remote Account this feature can not be used (all versions).
Version 7 or below - Select the Security button to enable the firewall and add the IP address to the SMTP service.
Version 8 or higher - Select System, Services, edit the SMTP service and select the Access tab. Check Restrict access to all services, enter the IP you want to block and set it to deny. Separate IP's with semi-colon.