CCSP Self-Study: Securing Cisco IOS Networks (SECUR)

Filtering Network Traffic

This section explains how to implement ACLs for mitigating the following threats:

• IP address spoofing— inbound

• IP address spoofing— outbound

• DoS TCP SYN attacks— blocking external attacks

• DoS TCP SYN attacks— using TCP intercept

• DoS smurf attacks

• Filtering ICMP messages— inbound

• Filtering ICMP messages— outbound

• Filtering traceroute

IP Address Spoof Mitigation

One method that attackers frequently use to gain information from a network is to try to appear as a trusted member of the network under attack. This is done by spoofing the source IP address in packets that are destined to the internal network under attack. The attacker simply changes the source IP address in the packet to an address that belongs to the internal ...