Message sender IP addresses go through IP reputation-based filtering. IP addresses are evaluated until the first match is found.
Messages from allowed sender IP addresses bypass IP reputation-based filtering at the MTA connection level and proceed to spam detection. Messages from blocked sender IP addresses are blocked.
The order of evaluation for IP addresses in the lists on the Approved and Blocked IP Addresses screen is based on which list contains the IP address or Classless Inter-Domain Routing (CIDR) block.
Evaluation is done in the following order:
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The IP Addresses list
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On the Approved screen
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On the Blocked screen
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The Country/Region list
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On the Approved screen
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On the Blocked screen
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The selected standard IP reputation database lists on the IP Reputation Settings screen
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The adjusted dynamic IP reputation database lists on the IP Reputation Settings screen
An IP address added to the IP Addresses list on the Approved screen will not be blocked even if that IP address is also in a CIDR block listed on the Blocked screen. Furthermore, that IP address will not be blocked even if it is also in the Known Spam Source standard IP reputation database list.
IP reputation-based filters use only IP address data to filter messages. You can also use sender email address and domain to filter incoming messages. Approved senders bypass IP reputation-based filtering at the MTA connection level.