55-5

Cisco ASA 5500 Series Configuration Guide using the CLI
Chapter55 Configuring the Botnet Traffic Filter
Information About the Botnet Traffic Filter
How the Botnet Traffic Filter Works

Figure 55-1 shows how the Botnet Traffic Filter works with the dynamic database plus DNS inspection

with Botnet Traffic Filter snooping.

Figure55-1 How the Botnet Traffic Filter Works with the Dynamic Database

Figure 55-2 shows how the Botnet Traffic Filter works with the static database.

Figure55-2 How the Botnet Traffic Filter Works with the Static Database
Security Appliance
DNS
Reverse
Lookup Cache
Infected
Host
Malware Home Site
209.165.201.3
Syslog Server
Dynamic
Database DNS Server
DNS Snoop
1 DNS Request:
bad.example.com
3Connection to:
209.165.201.3
2 DNS Reply:
209.165.201.3
Internet
Botnet Traffic
Filter
3b. Send
Syslog Message/Drop Traffic
1a. Match?
3a. Match?
2a. Add
248631
Security Appliance
DNS
Host Cache
Infected
Host
Malware Home Site
209.165.201.3
Syslog Server
Static
Database DNS Server
Botnet Traffic
Filter
3Connection to:
209.165.201.3
1a. DNS Request:
bad.example.com
Internet
3b. Send
Syslog Message/Drop Traffic
2a. Add
1Add entry:
bad.example.com
2 DNS Reply:
209.165.201.3
3a. Match?
248632