Clearsigned 文件无效，在 VirtualBox 上出现“NOSPLIT”（网络是否需要身份验证？）

Question

我刚刚在 Windows 10 托管的虚拟机上安装了 Ubuntu

我试图找到解决这个问题已经几个小时了：

Get:1 http://archive.ubuntu.com/ubuntu xenial InRelease [3,548 B]
Err:1 http://archive.ubuntu.com/ubuntu xenial InRelease
  Clearsigned file isn't valid, got 'NOSPLIT' (does the network require authentication?)
Get:2 http://archive.ubuntu.com/ubuntu xenial-updates InRelease [3,556 B]
Err:2 http://archive.ubuntu.com/ubuntu xenial-updates InRelease
  Clearsigned file isn't valid, got 'NOSPLIT' (does the network require authentication?)
Get:3 http://archive.ubuntu.com/ubuntu xenial-backports InRelease [3,558 B]
Err:3 http://archive.ubuntu.com/ubuntu xenial-backports InRelease
  Clearsigned file isn't valid, got 'NOSPLIT' (does the network require authentication?)
Get:4 http://archive.ubuntu.com/ubuntu xenial-security InRelease [3,557 B]
Err:4 http://archive.ubuntu.com/ubuntu xenial-security InRelease
  Clearsigned file isn't valid, got 'NOSPLIT' (does the network require authentication?)
Fetched 14.2 kB in 4s (3,174 B/s)
Reading package lists... Done
E: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/xenial/InRelease  Clearsigned file isn't valid, got 'NOSPLIT' (does the network require authentication?)
E: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/xenial-updates/InRelease  Clearsigned file isn't valid, got 'NOSPLIT' (does the network require authentication?)
E: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/xenial-backports/InRelease  Clearsigned file isn't valid, got 'NOSPLIT' (does the network require authentication?)
E: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/xenial-security/InRelease  Clearsigned file isn't valid, got 'NOSPLIT' (does the network require authentication?)
E: Some index files failed to download. They have been ignored, or old ones used instead.

• 我的连接工作正常：（在 Firefox 上）

• 当我使用 wget 时，我得到状态 200：

我发现这个类似的问题 sudo apt update 总是给出 Clearsigned 文件无效，得到“NOSPLIT”（网络是否需要身份验证？）但只有两个答案：

• 一：这表明这是我的 ISP 特有的网络问题。（我怎么能确定？那我该怎么做才能解决呢）
• 二：是代理问题，所以我做了如下配置

我应该<proxy>用什么代替？

Answer 1

替换<proxy>为您的代理地址。

例如，如果您的代理服务器是1.2.3.4并且端口是 1234，那么第一行应该是

Acquire::http::proxy "http://1.2.3.4:123

将其用于所有其他线路。