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TCP - UDP Protocol Analysis

TCP Header Anaylsis - Section 7: TCP Data Payload…

Finally, the last page of our incredible TCP Analysis. As most of you would expect, this section is dedicated to the DATA section that follows the TCP Header. The Data Section The following diagram…

TCP - UDP Protocol Analysis

TCP Header Anaylsis - Section 3: TCP Header Lengt…

The third field under close examination is the TCP Header length. There really isn't that much to say about the Header length other than to explain what it represents and how to interpret its values…

Linux - Unix

Linux BIND DNS - Part 5: Configure Secondary (Sla…

Setting up a Secondary (or Slave) DNS sever is much easier than you might think. All the hard work is done when you setup the Master DNS server by creating your database zone files and configuring th…

Ethernet Protocol, CSMA/CD, Collisions

Late Ethernet Collisions

Late collisions, on the other hand, are not normal and are usually the result of out of spec. cabling or a malfunctioning adapter. A late collision is defined as any collision that occurs after 512 b…

Palo Alto Networks

How to Register a Palo Alto Firewall and Activate…

This article explains how to register and activate your Palo Alto Firewall Appliance to obtain technical support, RMA hardware replacement, product updates, antivirus updates, wildfire, antispam upda…

Ethernet Protocol, CSMA/CD, Collisions

Migrating From Ethernet To Fast Ethernet

In this article we will analyze the following aspects of upgrading/migrating from 10Mbit Ethernet to 100Mbit Ethernet. Cabling Incompatible Implementations Repeaters In Fast Ethernet Replacemen…

Cisco Firewalls

Cisco ASA 5500-X Series Firewall with IPS, ASA CX…

The Cisco ASA Firewall 5500-X series has evolved from the previous ASA 5500 Firewall series, designed to protect mission critical corporate networks and data centers from today’s advanced security th…

VLAN Networks

VTP Protocol - In-Depth Analysis

The previous article introduced the VTP protocol, we examined how it can be used within a network, to help manage VLANs and ease the administrative overhead, providing a stress-free VLAN environment…

Ethernet Protocol, CSMA/CD, Collisions

The IEEE 802.3 Frame Format

The following is a description of the Ethernet Frame Format described in the IEEE 802.3 Specification. The 802.3 Specification defines a 14 byte Data Link Header followed by a Logical Link Control He…

Network Fundamentals

DoS & DDoS Attacks

A Denial of Service (DoS) attack is a malicious attempt to disrupt the normal functioning of a website, server or network by flooding it with traffic or overloading its resources. The aim of such an…

Linux - Unix

Configuring Linux to Act as a Firewall - Linux IP…

What exactly is a firewall? As in the non-computer world, a firewall acts as a physical barrier to prevent fires from spreading. In the computer world too, the firewall acts in a similar manner, only…

Cisco Routers

Configuring Site to Site IPSec VPN Tunnel Between…

Site-to-Site IPSec VPN Tunnels are used to allow the secure transmission of data, voice and video between two sites (e.g offices or branches). The VPN tunnel is created over the Internet public netwo…