Network Wizkid's Technical Knowledge Base

In this article, we will take a look at how to configure different types of NAT on the Cisco ASA post 8.4 software code. Accompanying this post is a video demonstration covering what has been discussed in this article. We will cover the following types of NAT: Static NAT Dynamic NAT Dynamic PAT Identity NAT Before jumping into the demonstrations I will explain the purpose of each type of NAT on the Cisco ASA. Overview of NAT NAT addresses can be defined as the following: Inside local address: This is the IP address that is assigned to a host on the inside of a network. The inside local address is most certainly bound to fall within the RFC 1918 reserved private IP address spaces. Inside global address: This is a globally routable IP address (public IP address) that can represent one or more inside local IP addresses to the outside world. Outside local address: This is the IP address of an outside host as it appears to the inside network. Outside global address: This is the IP addre...

C.I.A, is a well-known abbreviation that is known among those within the Information Security/IT community. In the world of information security you will find it in many books and articles when studying for certifications. So what is the CIA triad and how does it fit within information security? CIA triad is a model designed to guide company policies on information security and are considered the three most important pillars within information security. Confidentiality The letter ‘C’ is short for Confidentiality and should be used to identify sensitive data viewed only by those with the correct permissions. There are two types of data; data in motion and data at rest . Data in motion: is data that is traversing through a network or a series of networks to a destination. Imagine the following, a Postman has a letter he has picked up from the depot and it is addressed to you. He puts the letter in his bag along with other letters for your neighbors and proceeds to the area to deli...

In this article I will explain demultiplexing and how it works by walking through a .pcap file taken from the lab in the screenshot below. We will focus on the data flowing from PC1 and SW1 to R1’s ingress port. Demultiplexing (DEMUX) is the method in which the TCP/IP stack uses to determine if datagrams have been received correctly and if so, how should they be processed. Demultiplexing looks at certain fields at each layer of the TCP/IP stack, these fields include MAC addresses, IP addresses, protocols and ports. Checksums are also accounted for to verify the datagram hasn’t been damaged during transit. Physical I sent a DHCP request from PC1 into the network and captured the request on the Gigabyte interface connecting SW1 and R1, we will use the DISCOVER .pcap file to walk through demultiplexing. As shown in figure .1 , the Ethernet frame enters the ingress interface of R1 from PC1. We have lots of information to accompany the datagram but our main focus is the Encaps...