Linux Server Hardening
Below is an example check list for Linux server hardening – All ports except SSH, http is blocked. On some of the servers, DNS and...
Mobile Communication Services
One of the fastest growth rates in the telecommunications industry anywhere in the world is that of mobile radio communication devices. The basic architecture of...
Digitized Phone Services (E-10B)
Olden form of phone systems involved manual exchanges which involved a great task in switching and routing of calls to various subscribers that increased network...
Early Evolution of Data Commmunication Systems
It’s helpful for data communication and IT students to understand the evolution of Data communication systems. The first phase in the evolution of data communication...
Data Communication and its basic setup
Data Communications is the function of transferring a digital signal from one digital device to another. Data transmission and data communications mean two different things....
ARP (Address Resolution Protocol) in action
Suppose machine A wants to send its message packets to B which has the IP address 1B. A only knows B’s IP address and thus...
ARP – Address Resolution Protocol
ARP or Address Resolution Protocol is used to map Internet addresses to physical addresses. Address resolution is the process of mapping Internet IP addresses into...
Weaknesses of IP address
Below are couple major weaknesses of IP addresses – A machine cannot be assigned a permanent IP address i.e. it should change when the machine...
‘This’ network and ‘this’ host address
An IP address with all 0’s in the host id, refers to this particular and the IP addresses with all 0’s in the network id...
Network & Broadcast address
Network and Broadcast address are derived from the general IP addresses and are used for specific or reserved applications. Network address refers to the IP...
Internet Addresses
Internet address refers to the unique identification or address assigned to each machine in the physical network. The basic need for assigning Internet address is...
Internet Architecture
As shown above, the Internet consists of various physical networks (Net1 … Netn) connected together as a single large network. Each network may have host...
Internetworking Concept and Architectural Model
Internetworking is the technology that makes it possible to interconnect many disparate physical networks with diverse underlying hardware technologies and make them function as a coordinated...
ARPANET Technology
ARPANET (Advanced research project agency network) is the oldest wide area packet switched network build by the DARPA (Defense advanced research project agency). Physically ARPANET...
ProNET variation – Start topology
ProNET variation as star topology is as shown below – The 3 hosts are connected logically by a ring connection and physically by a start...
ProNET 10 Token recovery
ProNET 10 token recovery is essential to handle situations of loss of token when the host want to transmit. Such token loses occur due to...
ProNET Token Ring Technology
ProNET Token ring technology is an alternative to ethernet technology and it also works fairly good speeds. It uses token ring technology- Token ring network...
Ethernet Variations
Ethernet technology started with using the costly coaxial cables. Now it is possible to carry ethernet frames over cost-effective and cheaper twisted pair cables supporting...
Ethernet Bridges
Ethernet bridge is a fast computer with two Ethernet interfaces and a fixed program that improve upon the functions of repeaters by replicating the packets,...
Ethernet addressing and frame format
Ethernet Addresses refers to the unique physical/hardware address assigned or hardcoded on to the Ethernet interface card in 48 bits machine readable form. Physical ethernet...
Collission detection and Recovery in Ethernet
Ethernet data transmission enabled by TCP/IP is a best-effort delivery method. i.e the sender is given no information about whether the data packets were received...
Ethernet Hardware and basic architecture
A cross section of a Ethernet cable is as shown below – Ethernet is typically a 10Mbps local area packet switched network technology. The cross...
LAN, WAN and MAN
WAN (Wide Area Network) connects machines over widely separated geographical locations. A WAN usually consists of various packet switches installed at various points on the...
Differences between TCP/IP internet services and others
TCP/IP internet services and other internetworking services can be compared on the basis of following features of TCP/IP internet – Network Topology Independence While TCP/IP...
Internetworking
Internetworking is the technology that makes it possible to interconnect many disparate physical networks with diverse underlying hardware technologies and make them function as a coordinated...
ISDN – Integrated Services Digital Network
ISDN, though not popular in US, it is still one of the most popular data communication networks in UK, India and many other European countries....
Basics setup of Mobile Communication services
One of the fastest growing telecommunication industry is obviously mobile radio communication. Below figure shows a basic architecture of such a mobile communication network –...
Digitized Telephone services
In the past, we had manual exchanges which involved a great task in switching and routing of calls to various subscribers that increased network traffic...
Evolution of Data Communication Systems
Almost all of the Data communication systems across the world evolved from Telegraph systems. Later with developments in the telephone systems, it was now possible...
Data Communication – Basic Definition and setup
Data communication is the function of transporting digital signal from one digital device to another. Data transmission and data communications means two different things. Data...
Simple HTTP log analyzer
Here is a simple light weight HTTP analyzer written in PHP. I wrote this to brush up my skills writing schedulers for a typical LAMP...
How to stop bulk spam emails to my mail account?
If you are not one of the people who have had the bad experience of having your email account being subjected to a bulk spam...
Preferred Multithreading in C# ASP.NET
Parallel execution has been one of the core techniques of programming languages that enables and stabilizes the heavy orchestrated flow of information across information management...
Software Project Size
Software Project Size is of great importance since it determines the level of management controls and the types of tools and technologies required for a...
Software Engineering then and now
Software Engineering is and will be the backbone and driving force behind the technological advancements that we enjoy and that will lead us to greater...
Importance Of Design Patterns
Design patterns in general helps you to implement standardized and efficient solutions to software design and programming problems. Design patterns are not pure inventions like...