SenderBase Reputation Score (SBRS)

The SenderBase Reputation Score (SBRS) is a numeric value assigned to an IP address based on information from the SenderBase Reputation Service. The SenderBase Reputation Service aggregates data from over 25 public blacklists and open proxy lists, and combines this data with global data from SenderBase to assign a score from -10.0 to +10.0, as follows:

The lower (more negative) the score, the more likely that a message is spam. A score of -10.0 means that this message is “guaranteed” to be spam, while a score of 10.0 means that the message is “guaranteed” to be legitimate.


Using the SBRS, you configure the IronPort C-Series appliance to apply mail flow policies to senders based on their trustworthiness.You can also create message filters to specify “thresholds” for SenderBase Reputation Scores to further act upon messages processed by the system.

IronPort Articles provide a very clear diagram for the SBRS Work Flow:

1. SenderBase affiliates send real-time, global data

2. Sending MTA opens connection with the IronPort C-Series appliance

3. IronPort C-Series appliance checks global data for the connecting IP address

4. SenderBase Reputation Service calculates the probability this message is spam and

assigns a SenderBase Reputations Score

5. IronPort C-Series returns the response based on the SenderBase Reputation Score