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Static PAT

According to the definitions outlined in the NAT Terminology article, a Static PAT implies a translation of the IP address and Port, where the post-translation attributes are explicitly defined. There are multiple use cases for a Static PAT, but they all have one thing in common – a need to manually change the TCP or […]


Static NAT

According to the definitions outlined in the NAT Terminology article, a Static NAT implies a translation of just the IP address, where the post-translation IP addresses are explicitly defined. Making Internal Resources Accessible The typical use case for a Static NAT is for a Server on a Private IPv4 network to be reached externally from the […]


NAT Terminology

As discussed before, Network Address Translation, or NAT, is a process that involves translating Private IP addresses into Public IP addresses. There are different operations within NAT and understanding each of them requires understanding NAT terminology. NAT vs PAT Network Address Translation and Port Address Translation differ by modifying different headers in a data packet. […]


Why NAT?

Before we can discuss how NAT works, we must discuss the purpose of NAT and answer the question, “Why NAT?” In the original plan for the Internet, every host was meant to have its own unique IP address. This means if you had a network which had 30 hosts, you would need 30 unique IP […]


ARP in 5 Minutes

Here is a quick video that teaches the basics of Address Resolution Protocol (ARP) in less than 5 minutes. If you want to go deeper on ARP and all of its variants, check out the Address Resolution Protocol article series.


BGP Oldest Path

BGP is the predominant dynamic routing protocol used to exchange routes between different autonomous systems. BGP’s popularity lies in the Path Selection process which allows extremely granular control of the path for incoming and outgoing traffic. One of the steps in this process states that if a tie still exists between two paths, BGP will […]


Communication through Multiple Switches

In a previous article we demonstrated how a single switch functions. One of the most frequent requests I receive is asking how the process would be different if there were multiple switches. This article will illustrate the process using two switches. In the Packet Traveling series, we discussed the four specific functions of a switch: Learning, Flooding, Forwarding, […]


Address Resolution Protocol (ARP)

An IP address is the logical addressing scheme for nodes on a network. IP Addresses exist at the Network layer of the OSI Model and help facilitate the L3 goal of “end to end” delivery. A MAC address is the physical addressing scheme for individual NIC cards on each node of a network. MAC addresses […]