最近买了一个云耀云服务器，使用SSH 登录Linux服务器，使用sudo apt-get update出现如下错误：

Err:1 http://archive.ubuntu.com/ubuntu bionic InRelease                                                                    
  Cannot initiate the connection to archive.ubuntu.com:80 (2001:67c:1360:8001::24). - connect (101: Network is unreachable) Cannot initiate the connection to archive.ubuntu.com:80 (2001:67c:1360:8001::23). - connect (101: Network is unreachable) Could not connect to archive.ubuntu.com:80 (91.189.88.142), connection timed out Could not connect to archive.ubuntu.com:80 (91.189.88.152), connection timed out
Err:2 http://archive.ubuntu.com/ubuntu bionic-updates InRelease                                                            
  Cannot initiate the connection to archive.ubuntu.com:80 (2001:67c:1360:8001::24). - connect (101: Network is unreachable) Cannot initiate the connection to archive.ubuntu.com:80 (2001:67c:1360:8001::23). - connect (101: Network is unreachable)
Err:3 http://archive.ubuntu.com/ubuntu bionic-backports InRelease                                                          
  Cannot initiate the connection to archive.ubuntu.com:80 (2001:67c:1360:8001::24). - connect (101: Network is unreachable) Cannot initiate the connection to archive.ubuntu.com:80 (2001:67c:1360:8001::23). - connect (101: Network is unreachable)
Err:4 http://security.ubuntu.com/ubuntu bionic-security InRelease                                                          
  Cannot initiate the connection to security.ubuntu.com:80 (2001:67c:1562::18). - connect (101: Network is unreachable) Cannot initiate the connection to security.ubuntu.com:80 (2001:67c:1562::15). - connect (101: Network is unreachable) Cannot initiate the connection to security.ubuntu.com:80 (2001:67c:1360:8001::24). - connect (101: Network is unreachable) Cannot initiate the connection to security.ubuntu.com:80 (2001:67c:1360:8001::23). - connect (101: Network is unreachable) Could not connect to security.ubuntu.com:80 (91.189.88.142), connection timed out Could not connect to security.ubuntu.com:80 (91.189.88.152), connection timed out Could not connect to security.ubuntu.com:80 (91.189.91.39), connection timed out Could not connect to security.ubuntu.com:80 (91.189.91.38), connection timed out
Reading package lists... Done                                  
W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/bionic/InRelease  Cannot initiate the connection to archive.ubuntu.com:80 (2001:67c:1360:8001::24). - connect (101: Network is unreachable) Cannot initiate the connection to archive.ubuntu.com:80 (2001:67c:1360:8001::23). - connect (101: Network is unreachable) Could not connect to archive.ubuntu.com:80 (91.189.88.142), connection timed out Could not connect to archive.ubuntu.com:80 (91.189.88.152), connection timed out
W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/bionic-updates/InRelease  Cannot initiate the connection to archive.ubuntu.com:80 (2001:67c:1360:8001::24). - connect (101: Network is unreachable) Cannot initiate the connection to archive.ubuntu.com:80 (2001:67c:1360:8001::23). - connect (101: Network is unreachable)
W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/bionic-backports/InRelease  Cannot initiate the connection to archive.ubuntu.com:80 (2001:67c:1360:8001::24). - connect (101: Network is unreachable) Cannot initiate the connection to archive.ubuntu.com:80 (2001:67c:1360:8001::23). - connect (101: Network is unreachable)
W: Failed to fetch http://security.ubuntu.com/ubuntu/dists/bionic-security/InRelease  Cannot initiate the connection to security.ubuntu.com:80 (2001:67c:1562::18). - connect (101: Network is unreachable) Cannot initiate the connection to security.ubuntu.com:80 (2001:67c:1562::15). - connect (101: Network is unreachable) Cannot initiate the connection to security.ubuntu.com:80 (2001:67c:1360:8001::24). - connect (101: Network is unreachable) Cannot initiate the connection to security.ubuntu.com:80 (2001:67c:1360:8001::23). - connect (101: Network is unreachable) Could not connect to security.ubuntu.com:80 (91.189.88.142), connection timed out Could not connect to security.ubuntu.com:80 (91.189.88.152), connection timed out Could not connect to security.ubuntu.com:80 (91.189.91.39), connection timed out Could not connect to security.ubuntu.com:80 (91.189.91.38), connection timed out
W: Some index files failed to download. They have been ignored, or old ones used instead.

解决方法
参考之前写的文章 ubuntu下sudo apt-get update Sources 404 Not Found [IP: 91.189.92.200 80]解决办法

修改 etc/apt/sources.list：

//备份源文件
sudo cp -rfv /etc/apt/sources.list /etc/apt/sources.list.back

//编辑source.list文件
sudo vi /etc/apt/sources.list

全选快捷键：shift+v选中一行，shift+g调到结尾实现全选
删除所选择的内容：dd
按 i 进入插入模式，复制如下内容：

deb http://mirrors.163.com/ubuntu/ trusty main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ trusty-security main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ trusty-updates main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ trusty-proposed main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ trusty-backports main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ trusty main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ trusty-security main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ trusty-updates main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ trusty-proposed main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ trusty-backports main restricted universe multiverse

注意删除文件结尾不必要的文字，按 esc 键，再:wq 保存退出

此时再次执行sudo apt-get update，已经可以正常运行了，速度飞快～

Ign:1 http://mirrors.163.com/ubuntu trusty InRelease
Get:2 http://mirrors.163.com/ubuntu trusty-security InRelease [65.9 kB]
Get:3 http://mirrors.163.com/ubuntu trusty-updates InRelease [65.9 kB]
Get:4 http://mirrors.163.com/ubuntu trusty-proposed InRelease [65.9 kB]
Get:5 http://mirrors.163.com/ubuntu trusty-backports InRelease [65.9 kB]
Get:6 http://mirrors.163.com/ubuntu trusty Release [58.5 kB]   
Get:7 http://mirrors.163.com/ubuntu trusty-security/restricted Sources [4,931 B]
Get:8 http://mirrors.163.com/ubuntu trusty-security/main Sources [172 kB]
Get:75 http://mirrors.163.com/ubuntu trusty/multiverse i386 Packages [134 kB]
Fetched 30.9 MB in 8s (3,670 kB/s)                                                                                                                                                                          
Reading package lists... Done

至此，问题已经解决

备注：如果出现The following signatures couldn’t be verified because the public key is not available，请参考如下解决：
出错信息：

Ign:1 http://extras.ubuntu.com/ubuntu trusty InRelease                                                                         
Get:2 http://extras.ubuntu.com/ubuntu trusty Release [11.9 kB]                                                                          
Get:3 http://extras.ubuntu.com/ubuntu trusty Release.gpg [72 B]                                                                         
Ign:3 http://extras.ubuntu.com/ubuntu trusty Release.gpg                                                                                           
Err:4 http://cn.archive.ubuntu.com/ubuntu trusty InRelease                                                                                                                                                  
  Cannot initiate the connection to cn.archive.ubuntu.com:80 (2001:67c:1562::18). - connect (101: Network is unreachable) Cannot initiate the connection to cn.archive.ubuntu.com:80 (2001:67c:1562::15). - connect (101: Network is unreachable) Could not connect to cn.archive.ubuntu.com:80 (91.189.91.39), connection timed out Could not connect to cn.archive.ubuntu.com:80 (91.189.91.38), connection timed out
Err:5 http://cz.archive.ubuntu.com/ubuntu trusty-updates InRelease                                                    
  Cannot initiate the connection to cz.archive.ubuntu.com:80 (2001:67c:1360:8001::24). - connect (101: Network is unreachable) Cannot initiate the connection to cz.archive.ubuntu.com:80 (2001:67c:1360:8001::23). - connect (101: Network is unreachable) Cannot initiate the connection to cz.archive.ubuntu.com:80 (2001:67c:1562::15). - connect (101: Network is unreachable) Cannot initiate the connection to cz.archive.ubuntu.com:80 (2001:67c:1562::18). - connect (101: Network is unreachable) Could not connect to cz.archive.ubuntu.com:80 (91.189.88.142), connection timed out Could not connect to cz.archive.ubuntu.com:80 (91.189.91.39), connection timed out Could not connect to cz.archive.ubuntu.com:80 (91.189.91.38), connection timed out Could not connect to cz.archive.ubuntu.com:80 (91.189.88.152), connection timed out
Reading package lists... Done                               
W: GPG error: http://extras.ubuntu.com/ubuntu trusty Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 16126D3A3E5C1192
E: The repository 'http://extras.ubuntu.com/ubuntu trusty Release' is not signed.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.

执行如下命令：

//注意如下两句命令中的16126D3A3E5C1192需要替换为控制台中实际显示的值
sudo gpg --keyserver keyserver.ubuntu.com --recv 16126D3A3E5C1192
sudo gpg --export --armor 16126D3A3E5C1192 | sudo apt-key add -