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# IPv4
IPv4 개요
* 4개의 옥텟으로 구성된다. (1옥텟 = 8bit = 256개의 경우의 수)
* 총 32bit로 구성된 데이터
* 표현 가능한 주소 범위: 0.0.0.0 \~ 255.255.255.255
* 가장 앞자리는 IP class를 표현
* 내부 사설망 IP는 관리자가 임의로 IP를 할당해 사용 가능
* 단, 127.0.0.1은 사용 불가
* 외부 통신을 위해 외부 IP로 변환하는 NAT 서버를 사용
{% hint style="info" %}
"127.0.0.1"은 루프백(loopback) 주소로, 호스트 자체를 가리키므로 사설망 할당용으로 사용할 수 없다.
{% endhint %}
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