Address Translations
– Describe the purpose of having NAT (Network Address Translation) and PAT (Port Address Translation).
– Describe the difference between NAT (Network Address Translation) and PAT (Port Address Translation).
– Give an example for each of them.
– Describe them using images (please explain each part on the image that you use)
– Please list your reference and cite them appropriately.
The reference page should be on a separate page.
Address Translations
Network Address Translation is a technique where computer devices can share an IPv4 address due to shortages of the address. NAT has three basic concepts and they include Static NAT, Dynamic NAT, and PAT (Nfware, 2019). The purpose of NAT is to provide accessibility for devices outside the network. In more holistic terms, NAT is used in routing devices for conversion of private and public addresses. Packet headers are mostly re-written to facilitate for correct operation. For Static NAT, one-to-one translations from internal to external addresses is conducted. For Dynamic NAT several external IP addresses are distributed to automatically map inside global and local addresses. Port Address Translation (PAT) is often considered as a dynamic or overload type of NAT whose purpose is to save address space by mapping multiple internal addresses to a single address. PAT is known to allow routers to use one external address for several internal addresses. Since various users can access the internet via one public IP address when using PAT, it becomes more popular than NAT.
There are some differences between NAT and PAT (Geeks for Geeks, n.d). With NAT, internal addresses are commonly translated to public IP addresses. However, PAT performs the same function via Port numbers. While PAT may be considered as a part of NAT, it is more of a dynamic version of NAT since it maps IP addresses in global and local addresses automatically. On one hand, NAT uses IPv4 addresses but PAT does the same via Port numbers. As mentioned before, NAT has three basic types including static, dynamic and PAT. For the case of PAT, it only has two basic types which include Static and overload PAT.
The following are the examples of NAT and how they work:
Static NAT
In static NAT, the computer with the computer with the IP address 19.168.32.12 will always translate to 213.18.123.111. This is because the translation is always on a one-to-one basis (Software testing help, 2020). Among the overall network checksum, only the IP address is altered into a header checksum. It is mostly used when two IP networks are not compatible in addressing.
Dynamic NAT
For dynamic NAT, the IP addresses translate to the first available address within a given range. Mapping of unregistered private networks is done from a class of registered IP addresses.
Overloading NAT
For overloading NAT, this type is similar to Overloading PAT. Each IP addresses is translated via port addresses. Since it is known to translate one-to-many, it is referred o as dynamic NAT. for this type, the source addresses and destination IP addresses are constantly altered as they move back and forth.
Since overload NAT is similar to overload PAT, only static PAT will be reviewed below.
Static PAT
Static PAT uses a single Public IP address, unlike static NAT to host various services across local servers (Practical Networking, 2017). Using the example above, address 73.8.2.44 is a single IP enabled by Static PAT to host both HTTPS and HTTP using two individualistic local servers (10.4.4.42 and 10.4.4.41). Since routers are responsible for translation, they are loaded with two entries to represent Static PAT. These entries will be used to convert the addresses as defined when the packets cross over.
Overall, understanding NAT first gives a better understanding of PAT. While both technologies focus on translating IP addresses they function differently. NAT was initially created as a way to solve the issue of fewer IP addresses on the network. PAT however is an overload type of NAT.
References
Cisco Router Switch. (2013). How to Set Up PAT. Retrieved from http://ciscorouterswitch.over-blog.com/article-how-to-set-up-pat-port-address-translation-in-the-cisco-ios-114358100.html
Geeksforgeeks. (n.d). Difference between Network Address Translation (NAT) and Port Address Translation (PAT). Retrieved from https://www.geeksforgeeks.org/difference-between-network-address-translation-nat-and-port-address-translation-pat/
NFWARE. (2019). Types of Network Address Translation (NAT). Retrieved from https://nfware.com/blog/network-address-translation
Practical Networking. (2017). Static PAT. Retrieved from https://www.practicalnetworking.net/series/nat/static-pat/
Softwaretestinghelp. (2020). Network Address Translation (NAT) tutorial with exampples. Retrieved from https://www.softwaretestinghelp.com/network-address-translation-nat/
