Cisco Cisco Email Security Appliance C390 사용자 가이드

다운로드
페이지 418
Chapter 4      Quarantines
Working with Safelists and Blocklists
4-144
Cisco IronPort AsyncOS 7.3 for Email Daily Management Guide
OL-23080-01
  •
End-user tasks. End-users create their safelist and blocklist settings via the 
end-user spam quarantine. End users may need to log in (instead of clicking 
the link in the IronPort Spam Quarantine notification) to access their 
safelist/blocklist settings. From the end-user spam quarantine, end-users can 
create safelists and blocklists from the Options menu. Or, end-users can 
create safelist settings from the list of quarantined emails. For details about 
end-user tasks, see 
Message Delivery For Safelists and Blocklists
When you enable safelists and blocklists, the IronPort appliance scans the 
messages against the safelist/blocklist database immediately prior to anti-spam 
scanning. If the IronPort appliance detects a sender or domain that matches an end 
user’s safelist/blocklist setting, the message will be splintered if there are multiple 
recipients (and the recipients have different safelist/blocklist settings). For 
example, a message is sent to both recipient A and recipient B. Recipient A has 
safelisted the sender, whereas recipient B does not have an entry for the sender in 
either safelist or blocklist. In this case, the message may be split into two 
messages with two message IDs. The message sent to recipient A is marked as 
safelisted with an X-SLBL-Result-Safelist header, and skips anti-spam scanning, 
whereas the message bound for recipient B is scanned with the anti-spam 
scanning engine. Both messages then continue along the pipeline (through 
anti-virus scanning, content policies, etc.), and are subject to any settings 
configured. 
If a message sender or domain is blocklisted, the delivery behavior depends on the 
blocklist action settings. Similar to safelist delivery, the message is splintered if 
there are different recipients with different safelist/blocklist settings. The 
blocklisted message splinter is then quarantined or dropped, depending on the 
blocklist action settings. If the blocklist action is configured for quarantine, the 
message is scanned and eventually quarantined. If the blocklist action is 
configured as drop, the message is dropped immediately after safelist/blocklist 
scanning. 
Because the safelist and blocklists are maintained in the IronPort Spam 
Quarantine, delivery behavior is also contingent on other anti-spam settings. For 
example, if you configure the “Accept” mail flow policy in the HAT to skip 
anti-spam scanning, then users who receive mail on that listener will not have 
their safelist and blocklist settings applied to mail received on that listener.