Policy Routing Using Linux®

Summary

You have defined NAT within the Policy Routing structure. You have seen how a pure routing NAT structure runs with both asymmetric and single point setups. Using FastNAT you have explored how to translate entire address spaces from one to another bidirectionally.

You then worked through the uses of the NetFilter NAT constructs and saw how these constructs complement the FastNAT structure. You understand how each type of NAT has a use within the overall network structure. Also, you determined that the two structures do not at this time coexist with each other.

But as you think about these uses of NAT you begin to ponder why it will be important in the long term. In IPv4 NAT has grown from an esoteric oddity to a daily necessity. But you ...