1. (c) A. Mariën - Ubizen Exercises Network design and configuration

2. (c) A. Mariën - Ubizen Transparent NAT

3. (c) A. Mariën - Ubizen Before NAT internet router firewall LAN HUB WebServer 188.54.20.0/24 10.20.0.0/16 188.54.20.2

4. (c) A. Mariën - Ubizen After NAT: OK? internet router firewall LAN HUB 188.54.20.0/24 10.20.0.0/16 “188.54.20.2” WebServer 10.20.0.2 “188.54.20.2”10.20.0.2

5. (c) A. Mariën - Ubizen After NAT: Need ARP fix! internet router firewall LAN HUB 188.54.20.0/24 10.20.0.0/16 “188.54.20.2” WebServer 10.20.0.2 “188.54.20.2”10.20.0.2 MACIF1 MACIF2 MACIF1 = ARP(188.54.20.2)

6. (c) A. Mariën - Ubizen RFC 1027  Using ARP to implement transparent subnet gateways  Describes transparent subnet division using ARP

7. (c) A. Mariën - Ubizen Before HUB Machine A 10.4.5.1 MACA Machine B 10.4.5.3 MACB Machine C 10.4.5.2 MACC Machine D 10.4.5.4 MACD

8. (c) A. Mariën - Ubizen After HUB Machine A 10.4.5.1 MACA Machine B 10.4.5.3 MACB Machine C 10.4.5.2 MACC Machine D 10.4.5.4 MACD HUB gateway MACgwleft 10.4.5.253 MACgwright 10.4.5.254

9. (c) A. Mariën - Ubizen Gateway ARP  Left Macgwleft = ARP(10.4.5.2) Macgwleft = ARP(10.4.5.4) Macgwleft = ARP(10.4.5.253)  Right Macgwright = ARP(10.4.5.1) Macgwright = ARP(10.4.5.3) Macgwright = ARP(10.4.5.254)

10. (c) A. Mariën - Ubizen Gateway routes  Route to host 10.4.5.1 via 10.5.4.253  Route to host 10.4.5.3 via 10.5.4.253  Route to host 10.4.5.2 via 10.5.4.254  Route to host 10.4.5.4 via 10.5.4.254

11. (c) A. Mariën - Ubizen ARP for load balancing  N systems can handle same request  Use ARP proxy to provide load balancing

12. (c) A. Mariën - Ubizen Network card in promiscuous mode  What does it mean?  What does it imply?

13. (c) A. Mariën - Ubizen