Bài giảng Mạng máy tính nâng cao - Chương 13: Firewall

Bài giảng Mạng máy tính nâng cao - Chương 13: Firewall bao gồm những nội dung về Firewalls (Stateless packet filtering, Stateful packet filtering, Application Gateways); Intrusion Detection Systems (IDS), Denial of Service Attacks.
Nội dung trích xuất từ tài liệu:
Bài giảng Mạng máy tính nâng cao - Chương 13: FirewallMạng máy tính nâng cao-V11Firewalls & IDS OutlineFirewalls◦ Stateless packet filtering◦ Stateful packet filteringAccess Control Lists◦ Application GatewaysIntrusion Detection Systems (IDS)◦ Denial of Service Attacks2FirewallsFirewallisolates organization’s internal net from larger Internet, allowing somepackets to pass, blocking others.publicInternetadministerednetworkfirewall3Why Firewalls?prevent denial of service (DoS) attacks:• SYN flooding: attacker establishes many bogus TCPconnections, no resources left for “real” connections.prevent illegal modification/access of internal data.• e.g., attacker replaces CIA’s homepage with somethingelse.allow only authorized access to inside network (set ofauthenticated users/hosts)three types of firewalls:1. stateless packet filters2. stateful packet filters3. application gateways4Stateless Packet FilteringShould arriving packetbe allowed in?Departing packet letout?internal network connected to Internet via routerfirewall.router filters packet-by-packet, decision toforward/drop packet based on:◦◦◦◦source IP address, destination IP addressTCP/UDP source and destination port numbersICMP message typeTCP SYN and ACK bits.5