1. NAT-PAT-DHCP ผศ. ดร. อนันต์ ผลเพิ่ม Asst.Prof.Anan Phonphoem, Ph.D. anan@cpe.ku.ac.th http://www.cpe.ku.ac.th/~anan Computer Engineering Department Kasetsart University, Bangkok, Thailand

2. 2 of 26 Network Address Translation IP depletion Problem ? Conserve IP addresses Enable networks to use private IP addresses on internal networks Security ?

3. 3 of 26 Private IP address ClassRFC 1918CIDR prefix A10.0.0.0 – 10.255.255.25510.0.0.0/8 B172.16.0.0 – 172.16.255.255172.16.0.0/12 C192.168.0.0 – 192.168.255.255192.168.0.0/16

4. 4 of 26 NAT Operates at the border of a stub network

5. 5 of 26 NAT

6. 6 of 26 Configure NAT Static Translation Dynamic Translation

7. 7 of 26 Static Translation

8. 8 of 26 Dynamic Translation

9. 9 of 26 PAT (Overloaded NAT)

10. 10 of 26 PAT

11. 11 of 26 NAT command debug ip nat

12. 12 of 26 Disadvantages of NAT Delay Loss of end-to-end ability Might not work with some applications

13. 13 of 26 Dynamic Host Configuration Protocol (DHCP)

14. 14 of 26 DHCP Message

15. 15 of 26 Configure DHCP GW Reserved Static IP (e.g. for servers)

16. 16 of 26 Verifying DHCP

17. 17 of 26 DHCP Relay

18. 18 of 26 DHCP Relay