# IPv4

<details id="bkmrk-subnetting-a-subnet-"><summary>Subnetting a subnet --sunny way</summary>

<iframe allowfullscreen="allowfullscreen" frameborder="0" height="315" src="https://www.youtube-nocookie.com/embed/aVTEZHC2wdA" title="YouTube video player" width="560"></iframe>

</details><details id="bkmrk-class-b-id---subnett"><summary>Class B ID - Subnetting</summary>

<iframe allowfullscreen="allowfullscreen" frameborder="0" height="315" src="https://www.youtube-nocookie.com/embed/wuIdYxaV46Y" title="YouTube video player" width="560"></iframe>

</details>##### Aufbau IPv4 - Adresse  


[![external-content.duckduckgo.com.jpeg](https://doku.stnd.io/uploads/images/gallery/2022-03/scaled-1680-/F4qFnOeqZm9g0cwW-external-content-duckduckgo-com.jpeg)](https://doku.stnd.io/uploads/images/gallery/2022-03/F4qFnOeqZm9g0cwW-external-content-duckduckgo-com.jpeg)

- geschrieben in dotted Dezimal, also Dezimalzahlen durch Punkte getrennt
- jeder Block besteht aus 8 Bit, also einem Byte auch ein Octet genannt
- gesamte Adresse besteht aus vier Byte
- um mit der Adresse arbeiten zu können muss von Dezimal in Binär umgerechnet werden  
    dabei hilft das Rechnen mit Rest (Modulo)  
    Umrechnung am Beispiel von 199  
    <table border="1" style="border-collapse: collapse; width: 53.8874%; height: 268.2px;"><tbody><tr style="height: 29.8px;"><td style="width: 20.9485%; height: 29.8px; background-color: #ecf0f1;">Dividend  
    </td><td style="width: 5.7359%; height: 29.8px; background-color: #ecf0f1;">  
    </td><td style="width: 24.433%; height: 29.8px; background-color: #ecf0f1;">Divisor  
    </td><td style="width: 7.73793%; height: 29.8px; background-color: #ecf0f1;">  
    </td><td style="width: 26.6844%; height: 29.8px; background-color: #ecf0f1;">Quotient  
    </td><td style="width: 14.4644%; height: 29.8px; background-color: #ecf0f1;">Rest  
    </td></tr><tr style="height: 29.8px;"><td style="width: 20.9485%; height: 29.8px;">199  
    </td><td style="width: 5.7359%; height: 29.8px;">/  
    </td><td style="width: 24.433%; height: 29.8px;">2  
    </td><td style="width: 7.73793%; height: 29.8px;">=  
    </td><td style="width: 26.6844%; height: 29.8px; background-color: #2dc26b;">99  
    </td><td style="width: 14.4644%; height: 29.8px;">1  
    </td></tr><tr style="height: 29.8px;"><td style="width: 20.9485%; height: 29.8px; background-color: #2dc26b;">99  
    </td><td style="width: 5.7359%; height: 29.8px;">/  
    </td><td style="width: 24.433%; height: 29.8px;">2  
    </td><td style="width: 7.73793%; height: 29.8px;">=  
    </td><td style="width: 26.6844%; height: 29.8px; background-color: #f1c40f;">49  
    </td><td style="width: 14.4644%; height: 29.8px;">1  
    </td></tr><tr style="height: 29.8px;"><td style="width: 20.9485%; height: 29.8px; background-color: #f1c40f;">49  
    </td><td style="width: 5.7359%; height: 29.8px;">/  
    </td><td style="width: 24.433%; height: 29.8px;">2  
    </td><td style="width: 7.73793%; height: 29.8px;">=  
    </td><td style="width: 26.6844%; height: 29.8px;">24  
    </td><td style="width: 14.4644%; height: 29.8px;">1  
    </td></tr><tr style="height: 29.8px;"><td style="width: 20.9485%; height: 29.8px;">24  
    </td><td style="width: 5.7359%; height: 29.8px;">/  
    </td><td style="width: 24.433%; height: 29.8px;">2  
    </td><td style="width: 7.73793%; height: 29.8px;">=  
    </td><td style="width: 26.6844%; height: 29.8px;">12  
    </td><td style="width: 14.4644%; height: 29.8px;">0  
    </td></tr><tr style="height: 29.8px;"><td style="width: 20.9485%; height: 29.8px;">12  
    </td><td style="width: 5.7359%; height: 29.8px;">/  
    </td><td style="width: 24.433%; height: 29.8px;">2  
    </td><td style="width: 7.73793%; height: 29.8px;">=  
    </td><td style="width: 26.6844%; height: 29.8px;">6  
    </td><td style="width: 14.4644%; height: 29.8px;">0  
    </td></tr><tr style="height: 29.8px;"><td style="width: 20.9485%; height: 29.8px;">6  
    </td><td style="width: 5.7359%; height: 29.8px;">/  
    </td><td style="width: 24.433%; height: 29.8px;">2  
    </td><td style="width: 7.73793%; height: 29.8px;">=  
    </td><td style="width: 26.6844%; height: 29.8px;">3  
    </td><td style="width: 14.4644%; height: 29.8px;">0  
    </td></tr><tr style="height: 29.8px;"><td style="width: 20.9485%; height: 29.8px;">3  
    </td><td style="width: 5.7359%; height: 29.8px;">/  
    </td><td style="width: 24.433%; height: 29.8px;">2  
    </td><td style="width: 7.73793%; height: 29.8px;">=  
    </td><td style="width: 26.6844%; height: 29.8px;">1  
    </td><td style="width: 14.4644%; height: 29.8px;">1  
    </td></tr><tr style="height: 29.8px;"><td style="width: 20.9485%; height: 29.8px;">1  
    </td><td style="width: 5.7359%; height: 29.8px;">/  
    </td><td style="width: 24.433%; height: 29.8px;">2  
    </td><td style="width: 7.73793%; height: 29.8px;">=  
    </td><td style="width: 26.6844%; height: 29.8px;">0  
    </td><td style="width: 14.4644%; height: 29.8px;">1</td></tr></tbody></table>
    
    Reste werden von unten nach oben aufgeschrieben, somit ergibt sich aus dem Beispiel die binäre Zahl:  
    11000111