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Cisco Intrusion Prevention System Appliance and Module Installation Guide for IPS 7.1
OL-24002-01
Appendix E Troubleshooting
When to Disable Anomaly Detection
When to Disable Anomaly Detection
If you have anomaly detection enabled and you have your sensor configured to see only one direction of
traffic, you should disable anomaly detection. Otherwise, you will receive many alerts, because anomaly
detection sees asymmetric traffic as having incomplete connections, that is, like worm scanners, and fires
alerts.
To disable anomaly detection, follow these steps:
Step 1
Log in to the CLI using an account with administrator privileges.
Step 2
Enter analysis engine submode.
sensor#
configure terminal
sensor(config)#
service analysis-engine
sensor(config-ana)#
Step 3
Enter the virtual sensor name that contains the anomaly detection policy you want to disable.
sensor(config-ana)#
virtual-sensor vs0
sensor(config-ana-vir)#
Step 4
Disable anomaly detection operational mode.
sensor(config-ana-vir)#
anomaly-detection
sensor(config-ana-vir-ano)#
operational-mode inactive
sensor(config-ana-vir-ano)#
Step 5
Exit analysis engine submode.
sensor(config-ana-vir-ano)#
exit
sensor(config-ana-vir)#
exit
sensor(config-ana-)#
exit
Apply Changes:?[yes]:
Step 6
Press
Enter
to apply your changes or enter
no
to discard them.
For More Information
For more information about Worms, refer to
Worms
.
Troubleshooting Global Correlation
Make sure you observe the following when configuring global correlation:
•
Because global correlation updates occur through the sensor management interface, firewalls must
allow port 443/80 traffic.
•
You must have an HTTP proxy server or a DNS server configured to allow global correlation
features to function.
•
You must have a valid IPS license to allow global correlation features to function.
•
Global correlation features only contain external IP addresses, so if you position a sensor in an
internal lab, you may never receive global correlation information.
•
Make sure your sensor supports the global correlation features.
•
Make sure your IPS version supports the global correlation features.