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Exchange Anti-Spam Toolkit Which Anti-Spam filters are built-in to Exchange Server?

The Sender Filter, Connection Filter, Content Filter and Recipient Filter are included with Exchange. All of the built-in Exchange Agents, and the equivalent page in QSS Exchange Anti-Spam Toolkit, are shown in the table below.

Built-in Exchange Agent QSS Exchange Anti-Spam Toolkit Page Description Supported Exchange Roles
Sender Filter Agent Sender Filter
  • Blocking of specific sender addresses and domains
  • Blocking of messages with blank senders
Mailbox & Edge Transport
Sender ID Agent Sender ID Validation
(Sender Filter)
  • Blocking of Hard SPF failures
Mailbox & Edge Transport
Protocol Analysis Agent Sender Reputation
(Sender Filter)
  • Blocking based on Open Proxy detection
  • Calculated Sender Reputation Level (SRL) based on HELO/EHLO domain validation, Reverse DNS lookup and analysis of historical SCL ratings for the sender
Mailbox & Edge Transport
Connection Filtering Agent Connection Filter
  • Blocking or allowing of specific IP addresses
  • IP Allow and Block List Providers (also known as IP-based DNSBL services)
  • Exceptions for specific recipient addresses
Mailbox & Edge Transport1
Content Filter Agent Content Filter
  • Blocking or allowing of specific words or phrases
  • Calculated Spam Confidence Level (SCL) based on analysis of message content
Mailbox & Edge Transport
Recipient Filter Agent Recipient Filter
  • Validation of recipient addresses during SMTP session
  • Blocking of specific recipient addresses
Edge Transport Only

1 The Connection Filtering agent is only installed on Edge Transport servers when using the script provided with Exchange. However, QSS Anti-Spam Toolkit provides a script to install it on Mailbox Servers.

You can choose to enable or disable each of the anti-spam filters independently.

Mailbox Junk Configuration

The Mailbox Junk Configuration allows different SCL thresholds to be defined for each mailbox for Delete, Reject, Quarantine and Junk actions. The user-configurable lists of blocked and allowed senders can move messages into the Junk Email folder, but cannot delete, reject or quarantine messages.

All of the Mailbox Junk settings can be managed using the Mailbox Junk Config page in QSS Exchange Anti-Spam Toolkit.