Introduction
This document describes how the SenderBase Reputation Score (SBRS) for your Cisco Secure Email Gateway is determined.
Prerequisites
Cisco recommends that you have knowledge of these topics:
- Cisco Secure Email Gateway (ESA)
- All versions of AsyncOS
SBRS Determination
The SBRS value is the IP address overall reputation for sending email on the Internet. SenderBase incorporates several variables into the score. Some of these variables are: spam traps, public Blocklists, user complaints, and volume data.
The SBRS scoring is from +10.0 to -10.0, where positive scores indicate a good reputation and negative scores indicate a bad reputation. The further the number is from zero, the more data supports that determination. IP addresses with an SBRS of None are senders who send a very low volume of mail or where there needs to be more data to determine a score.
Senders who suddenly have a significant percentage increase in mail volume see their scores drop one to two points. Unexpected rise in mail volume is often related to spammers and infected hosts sending massive amounts of mail. If the IP address is new and sends legitimate mail, the score rises in a few days.
Mail Gateways can block or rate-limit messages from senders based on the SBRS of the connecting IP address. The exact SBRS range and action varies from installation to installation. The most common configuration is to rate-limit scores of None and slightly negative, while more negative scores are blocked.
You can get general SenderBase information from Cisco Talos. This site includes any Blocklist listings that affect the SBRS of a given IP address. However, only Cisco customers and employees can discover the exact SBRS of a given IP address. For further assistance and information on a given IP address, please get in touch with Cisco Support.
Additional Information
Cisco Secure Email Gateway Documentation
Secure Email Cloud Gateway Documentation
Cisco Secure Email and Web Manager Documentation
Cisco Secure Product Documentation
Related Information