In this article, we will illustrate the Cisco NAT configuration on IOS Routers. This is a follow up article to the Network Address Translation article series which thoroughly covered the operation of NAT and answers the questions “What is NAT?” and “How does NAT work?“. There are only four types of network address translation: Static NAT, Static PAT, […]
VPN with Overlapping Networks
December 5, 2017 By 10 Comments
When connecting two sites together using a Virtual Private Network (VPN), a common issue that is encountered is trying to build a VPN with overlapping networks — where both sites happen to use the same Private IP addresses. In such cases, hosts on one side of the VPN tunnel will be unable to communicate with […]
Cisco NAT Terminology
November 15, 2017 By 4 Comments
Cisco has created some NAT terminology which explicitly refer to the IP addresses and/or ports involved in Network Address Translation (NAT). While discussing the addresses involved in a NAT, using the terms like “Source” and “Destination” are common. However, using such terms can create some ambiguity. Specifically, the terms “Source” and “Destination” can create confusion […]
Network Address Translation (NAT)
November 8, 2017 By 7 Comments
Every device on the Internet has an IP address. The IP address serves as the device’s identification – much like how a phone number identifies a particular phone. When devices communicate on the Internet, they are sending data from their IP address to the IP address of their intended destination. Sometimes, while data is en […]
NAT Terminology Disambiguation
November 5, 2017 By 14 Comments
If you’ve made it here, then at this point you should have a solid understanding of each of the four types of translation that can exist: Static NAT, Static PAT, Dynamic PAT, and Dynamic NAT. Moreover, you have an understanding of Policy NAT and Twice NAT, which are simply two different ways of implementing the […]
Policy NAT and Twice NAT
November 1, 2017 By 9 Comments
Every type of NAT we have discussed so far have two things in common. The first is that only the source of the packet is used to make a NAT decision. The second is that only the source of the outbound packet is translated. Policy NAT and Twice NAT are two ways of performing any […]
Dynamic NAT
October 25, 2017 By 6 Comments
According to the definitions outlined in the NAT Terminology article, a Dynamic NAT implies a translation of just the IP address, where the post-translation attributes are selected by the router. In a Dynamic NAT, a multitude of hosts with private IP addresses can share an equal or fewer amount of public IP addresses. It may […]
Dynamic PAT
October 18, 2017 By 12 Comments
According to the definitions outlined in the NAT Terminology article, a Dynamic PAT implies a translation of the IP address and Port, where the post-translation attributes are selected by the router. Dynamic PAT is the most common of the types of address translation we will discuss in this article series. Dynamic PAT is used any […]