1 / 6

Network Address Translation

Network Address Translation. Current problems with IP addresses: Address depletion Scaling in routing Solutions: IPv6 CIDR NAT. Network Address Translation. What is NAT?

beverlyh
Download Presentation

Network Address Translation

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Network Address Translation • Current problems with IP addresses: • Address depletion • Scaling in routing • Solutions: • IPv6 • CIDR • NAT

  2. Network Address Translation • What is NAT? • Informally, NAT is a method of connecting multiple computers on a local network to an external network using one IP address. • NAT can be incrementally deployed and only the local network routers need to be modified to implement NAT. • Backbone routers need not be modified.

  3. Network Address Translation Basic operation: NAT NAT Source -> 10.33.96.5: 2000 Destn. -> 198.76.28.4: 600 Source -> 198.76.28.4: 600 Destn. -> 198.76.29.7: 500 Reverse Translation Translation Source -> 198.76.29.7: 500 Destn. -> 198.76.28.4: 600 Source -> 198.76.28.4: 600 Destn. -> 10.33.96.5: 2000

  4. Network Address Translation • Routing across NAT: • Local addresses are hidden from backbone. • Backbone-partitioned networks need special handling using tunneling. • Header manipulations: • IP checksum should be changed. • For applications like FTP, application data should be modified which might require changing the TCP sequence no.s and acknowledgement no.s

  5. Network Address Translation • ICMP messages need a lot of modifications when they pass through a NAT – two address modifications and three checksum modifications. • Disadvantages: • NAT heavily violates the layering principle by looking into the transport and application layers. • Applications that contain IP address in their data cannot work through NAT unless NAT knows the exact occurrences.

  6. Network Address Translation • NAT reduces the options for providing security because any application data that contains IP addresses cannot be encrypted. • NAT provides privacy by hiding the local addresses but this makes detecting of attacks like mail spam difficult. • Conclusion: • NAT has several negative characteristics but it could still act as a short-term solution to the address depletion and scaling problems.

More Related