> For the complete documentation index, see [llms.txt](https://philipzheng.gitbook.io/docker_practice/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://philipzheng.gitbook.io/docker_practice/advanced_network.md).

# 進階網路設定

本章將介紹 Docker 的一些進階網路設定和選項。

當 Docker 啟動時，會自動在主機上建立一個 `docker0` 虛擬橋接器，實際上是 Linux 的一個 bridge，可以理解為一個軟體交換機。它會在掛載到它的網卡之間進行轉發。

同時，Docker 隨機分配一個本地未占用的私有網段（在 [RFC1918](http://tools.ietf.org/html/rfc1918) 中定義）中的一個位址給 `docker0` 介面。比如典型的 `172.17.42.1`，網路遮罩為 `255.255.0.0`。此後啟動的容器內的網卡也會自動分配一個同一網段（`172.17.0.0/16`）的網址。

當建立一個 Docker 容器的時候，同時會建立了一對 `veth pair` 介面（當資料包發送到一個介面時，另外一個介面也可以收到相同的資料包）。這對介面一端在容器內，即 `eth0`；另一端在本地並被掛載到 `docker0` 橋接器，名稱以 `veth` 開頭（例如 `vethAQI2QT`）。透過這種方式，主機可以跟容器通訊，容器之間也可以相互通訊。Docker 就建立了在主機和所有容器之間一個虛擬共享網路。

![Docker 網路](/files/-LvLdneHNQuU79ne0TM_)

接下來的部分將介紹在一些場景中，Docker 所有的網路自訂設定。以及透過 Linux 命令來調整、補充、甚至替換 Docker 預設的網路設定。


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