Troubleshooting NAT

Network Address Translation (NAT) is fairly easy to implement but because it is intricately integrated into so many security implementations, it can be tricky to troubleshoot. We will focus on NAT's implementation on Cisco routers in this section. We will talk about NAT issues on the PIX in a later section.

NAT Order of Operations

The first thing to be aware of when troubleshooting NAT is the order in which NAT takes place. Understanding this can eliminate many problems. Table 24-1 lists the order of operations of various features vis-á-vis NAT. “Inside” is generally the private network behind the router, and “outside” is the network on the public side of the router.

Table 24-1. Order in Which Various Operations Are Performed ...

Get Network Security Principles and Practices now with the O’Reilly learning platform.

O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.