# Binary Rules

## FIRST CONVERT ADD INTO BINARY

### 1. To workout the Network/Subnet Address

*   **Fill the host portion of Address with Binary 0's (then convert it to Decimal)**

    **2. To workout the First Host Address in a Subnet**
*   **Fill the host portion of the Address with Binary 0's except for the last bit which is set to Binary 1 (then convert it to Decimal)**

    **3. To workout the Last Host Address in a Subnet**
*   **Fill the host portion of the Address with Binary 1's except for the last bit which is set to 0. (then convert it to Decimal)**

    **4. To workout the Broadcast Address**
* **Fill the host portion of the Addresses with Binary 0's except for the last bit which is set to 1.(then convert it to Decimal)**

#### Why only work on the Host Portion?

* Because mask indicates Number of bits on the Network Side (already reserved)
* /24 = 255.255.255.0
* Hence we only work on the Host side

Practical Example:

* [Subnetting Binary Method Example 1](https://app.gitbook.com/@mudassirs46/s/network-fundamentals/~/drafts/-MRZ8l67L5MHnaQIEh9W/binary-method-example-1)
* [Subnetting Binary Method Example 2](https://app.gitbook.com/@mudassirs46/s/network-fundamentals/~/drafts/-MRZ8l67L5MHnaQIEh9W/binary-method-example-2)
* [Subnetting Binary Method Example 3](https://app.gitbook.com/@mudassirs46/s/network-fundamentals/~/drafts/-MRZ8l67L5MHnaQIEh9W/binary-method-example-3)

## Reference:

* [https://www.udemy.com/course/cisco-ccent-icnd1-100-105-complete-course-sims-and-gns3/learn/lecture/6087496#overview](https://www.udemy.com/course/cisco-ccent-icnd1-100-105-complete-course-sims-and-gns3/learn/lecture/6087496#overview)
