Previous Topic: SYN-Only Packet SourcesNext Topic: High and Variable Volume-Out


High Packet Fan Out

The High Packet Fan Out sensor looks for packets that fan out from a single host to many hosts. Packet fanning is typical of a spreading virus or worm. A High Packet Fan Out anomaly is a primary type of anomaly, which typically occurs in conjunction with another type of anomaly.

Troubleshooting a High Packet Fan Out Alert

An alert from the High Packet Fan Out Sources sensor may indicate a spreading virus or worm infection. Some viruses or worms operate by creating "zombie" hosts that spread the infection in a fan-out pattern.

If you suspect a virus infection, use CA Anomaly Detector to identify each offending host, then use a firewall or ACL to try to block the host from sending data on the network. You also can take the affected server offline.