當 resolv.conf 被覆蓋時，如何設定我的 DNS？

Question 1

base我相信如果您想覆蓋 DNS 名稱伺服器，您只需在 .txt下的檔案中添加與此類似的行即可resolv.conf.d。

例子

筆記：在開始之前，請確保安裝了以下軟體包，apt install resolvconf.

$ sudo vim /etc/resolvconf/resolv.conf.d/base

然後將您的名稱伺服器清單放入如下所示：

nameserver 8.8.8.8
nameserver 8.8.4.4

最後更新resolvconf：

$ sudo resolvconf -u

如果您查看手冊頁，resolvconf它描述了/etc/resolvconf/resolv.conf.d/.

   /etc/resolvconf/resolv.conf.d/base
          File  containing  basic  resolver  information.  The lines in this 
          file are included in the resolver configuration file even when no
          interfaces are configured.

   /etc/resolvconf/resolv.conf.d/head
          File to be prepended to the dynamically generated resolver 
          configuration file.  Normally this is just a comment line.

   /etc/resolvconf/resolv.conf.d/tail
          File to be appended to the dynamically generated resolver 
          configuration file.  To append nothing, make this  an  empty  
          file.   This file is a good place to put a resolver options line 
          if one is needed, e.g.,

              options inet6

即使文件頂部有警告head：

$ cat /etc/resolvconf/resolv.conf.d/head
# Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8)
#     DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN

此警告的存在是為了在建立這些檔案時，該警告最終將進入resolv.conf這些檔案將用於生成的結果檔案中。因此，您也可以輕鬆地將nameserver上述文件中的行新增base至該head文件。

參考

Answer

base我相信如果您想覆蓋 DNS 名稱伺服器，您只需在 .txt下的檔案中添加與此類似的行即可resolv.conf.d。

例子

筆記：在開始之前，請確保安裝了以下軟體包，apt install resolvconf.

$ sudo vim /etc/resolvconf/resolv.conf.d/base

然後將您的名稱伺服器清單放入如下所示：

nameserver 8.8.8.8
nameserver 8.8.4.4

最後更新resolvconf：

$ sudo resolvconf -u

如果您查看手冊頁，resolvconf它描述了/etc/resolvconf/resolv.conf.d/.

   /etc/resolvconf/resolv.conf.d/base
          File  containing  basic  resolver  information.  The lines in this 
          file are included in the resolver configuration file even when no
          interfaces are configured.

   /etc/resolvconf/resolv.conf.d/head
          File to be prepended to the dynamically generated resolver 
          configuration file.  Normally this is just a comment line.

   /etc/resolvconf/resolv.conf.d/tail
          File to be appended to the dynamically generated resolver 
          configuration file.  To append nothing, make this  an  empty  
          file.   This file is a good place to put a resolver options line 
          if one is needed, e.g.,

              options inet6

即使文件頂部有警告head：

$ cat /etc/resolvconf/resolv.conf.d/head
# Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8)
#     DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN

此警告的存在是為了在建立這些檔案時，該警告最終將進入resolv.conf這些檔案將用於生成的結果檔案中。因此，您也可以輕鬆地將nameserver上述文件中的行新增base至該head文件。

參考

Question 2

我也對這個問題感興趣，我嘗試了@sim提出的解決方案。

為了測試它，我把

nameserver 8.8.8.8

在/etc/resolvconf/resolv.conf.d/base和

nameserver 8.8.4.4

在/etc/resolvconf/resolv.conf.d/head

然後我重新啟動網絡

sudo service network-manager restart

結果/etc/resolv.conf看起來像

# Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8)
#     DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN
nameserver 8.8.4.4
nameserver 127.0.1.1

並nm-tool指出 dns 伺服器是

DNS:             208.67.222.222
DNS:             208.67.220.220

這是我的路由器提供的。另一方面，挖掘地址表明

;; Query time: 28 msec
;; SERVER: 8.8.4.4#53(8.8.4.4)

如果我是對的，我從這一切中得出的結論是

resolvonf 僅讀取“head”部分：“base”部分以某種方式由 dnsmasq 控制
無論 dhcp 提供的伺服器如何，dnsserver 實際上都被強制為 8.8.4.4，但是您會失去 dnsmasq 提供的緩存，因為請求始終發送到 8.8.4.4
dnsmasq 仍然僅使用 dhcp 提供的 dnsserver。

總而言之，它有效，但我認為這不是所要求的預期結果。我認為更接近的解決方案如下。編輯

sudo vim /etc/dhcp/dhclient.conf

然後加

supersede domain-name-servers 8.8.8.8;

結果如下：resolv.conf僅包含127.0.0.1，這意味著呼叫了dnsmasq快取並且nm-tool說

DNS:             8.8.8.8

這表示如果搜尋的名稱不在快取中，則在 8.8.8.8 上請求，而不是在 dhcp 提供的伺服器上請求。

另一個（也許更好）選項是使用“prepend”而不是“supersede”：這樣，如果 8.8.8.8 未解析該名稱，則請求將回退到其他伺服器。事實上，nm-tool 說

DNS:             8.8.8.8    
DNS:             208.67.222.222
DNS:             208.67.220.220

Answer