Recent Articles Changed
Email - Blacklist

Modified Thursday 28-09 08:04

A blacklist is a list of email or ip that are not trusted and should be blocked

Email (Internet Message)

Modified Thursday 28-09 08:01

An Email is just a document known as the MimeMessage or Internet Message Format that: is send and received between email server and managed via a client known as the Mail User Agent This is in the marketing session because this is an important...

What are email headers?

Modified Thursday 28-09 08:00

Email header are the most important part for email routing and this articles regroups the main logic about them

Card Puncher Data Processing
Server Name Indication (SNI)

Modified Tuesday 26-09 10:15

Server_Name_Indication is an extension to the TLS computer networking protocol by which a client indicates which hostname it is attempting to connect to at the start of the handshaking process. It's the TLS’s equivalent of the HTTP Host header and...

Card Puncher Data Processing

Modified Tuesday 26-09 10:14

openssl is a command line tool that: * permits testing, managing, and seeing what happens in a TLS world (ie new name for SSL) * can act as a network client/server See Obtain a valid Certificate for a Secured Web site Syntax With...

Map Of Internet 1973
Network - netcat (nc, ncat)

Modified Tuesday 26-09 10:11

netcat is a net client/server command line tool for TCP or UDP protocol. It can: reads and writes data across network connections acts as a client but also as a server You can see it as the equivalent of telnet It borrows its name from: ...

The port on a computer is part of the location of a service

Modified Tuesday 26-09 09:44

This article is about the network port, what it is, how we use it and more

Network Simple Route
Network - Route

Modified Tuesday 26-09 09:24

If you want to use TCP/IP to send a data packet, the network layer (in the OSI layer model or the IP layer) must determine if and how the target IP address can be accessed. The routing information necessary for this is stored in the routing table....

Recent Articles Created
What is the Return-Path for an email?

Created Thursday 28-09 07:58

The Return-Path is an email message header that: contains an email adress where administrative messages are sent. Example: bounced messages feedback.

Map Of Internet 1973
Net Client

Created Tuesday 26-09 08:44

This page is clients that can send data to a socket. openssl client

Windows Network Protocol Sysinfo
Network Layer

Created Tuesday 26-09 07:24

This page is the protocol that implements Network: Addressing, routing, and traffic control This the layer 4 of the OSI mdoel. These protocols are implemented by the OS but maybe implemented by an OS Application - See Internet Protocol...

Firewalld - Backend

Created Monday 25-09 07:11

firewalld uses as backend: nftables (default) iptables (deprecated) The configuration is firewalld system configuration.

Firewalld - NFTABLES

Created Monday 25-09 07:09

nftables is the current backend of firewalld

Map Of Internet 1973
Internet Control Message Protocol (ICMP)

Created Sunday 24-09 04:33

The are message used to: exchange information, and error information in the Internet Protocol (IP). address-unreachable bad-header beyond-scope communication-prohibited destination-unreachable echo-reply echo-request ...

Firewalld - Policy

Created Sunday 24-09 04:08

A policy applies a set of rules to traffic flowing between zones. The policy affects traffic in a stateful unidirectional manner, e.g. from: an ingress zone: zoneA to an egress zone: zoneB. A policy's relationship to zones is defined by assigning:xmconfiguration...

ICMP types

Created Sunday 24-09 03:49

can be used in Firewalld to limit the exchange of ICMP messages.

Data all the way

Always keep one hand firmly on data, Amos liked to say.

Data is what set psychology apart from philosophy, and physics from metaphysics.

Amos Tversky (The undoing project)
Data Warehouse Subsystem

Data Warehouse Subsystems

Developing a data warehouse means assembling a lot of subsystems in order to create a whole and coherent data application.

Discovers the 34 Kimball Subsystems and drill down to discover them

Data Warehouse Subsystems

Card Puncher Data Processing

Data Processing

Data processing has changed a lot since 1940 :) and luckily, we are not using punch card anymore.

Stream processing is becoming the norm in data integration task while batch processing stays the king in data analysis.

Data Processing

ENIAC, 1946

The first fully electronic digital computer

Eniac 1946

Table Recursion Rectangle

Data Modeling

Data Modeling is the translation of process into the world of data. The process is tricky but not insurmountable.

Data Modeling

Dimensional Data Modeling

Dimensional Data Modeling permits you to model a (hyper)cube and analyse a process through different perspective. You define dimensions, measures and metrics.

Dimensional Data Modeling

Most programs process some input to produce some output; that’s pretty much the definition of computing.

Function Home


A Function is the basic block of all reusable code component. It is also becoming the central component of any serverless architecture.


Knowledge isn't free. You have to pay attention.

Computing Division at the Department of the Treasury, mid 1920s

Computing Division At The Dept Of The Treasur 1920

Remington Rand Univac

Medieval Counting Table

Table / Relation

The table format (known also as a relation) is the most important data structure used in data analysis. Did you know that its name originate from the medieval counting table ?


Education isn't something you can finish.

Richard Feynman
Task Runner