Section Four What a Stateless ipchains Firewall Cannot Protect Against

• Spoofing real IP addresses

• Stealth scans

• Some denial of service attacks

• Misuses of application protocols (e.g. LOKI, FTP port command to initiate port scans from an intermediary or establish connections behind the firewall)

• Viruses and trojans

• Applications using unusual or server callback protocols

Notes: