问题描述

E: Failed to fetch http://cn.archive.ubuntu.com/ubuntu/pool/universe/x/x264/libx264-155_0.155.2917+git0a84d98-2_amd64.deb  Connection failed [IP: 91.189.91.39 80]
E: Failed to fetch http://cn.archive.ubuntu.com/ubuntu/pool/universe/x/x265/libx265-179_3.2.1-1build1_amd64.deb  Connection failed [IP: 91.189.91.39 80]
E: Unable to fetch some archives, maybe run apt-get update or try with --fix-missing?

sudo apt-get update --fix-missing

Err:1 http://cn.archive.ubuntu.com/ubuntu focal InRelease                      
  Connection failed [IP: 91.189.91.39 80]
Err:2 http://security.ubuntu.com/ubuntu focal-security InRelease               
  Connection failed [IP: 91.189.91.38 80]
Hit:3 http://ppa.launchpad.net/maarten-baert/simplescreenrecorder/ubuntu focal InRelease
Err:4 http://cn.archive.ubuntu.com/ubuntu focal-updates InRelease            
  Connection failed [IP: 91.189.91.38 80]
Err:5 http://cn.archive.ubuntu.com/ubuntu focal-backports InRelease
  Connection failed [IP: 91.189.91.39 80]
Reading package lists... Done                          
W: Failed to fetch http://cn.archive.ubuntu.com/ubuntu/dists/focal/InRelease  Connection failed [IP: 91.189.91.39 80]
W: Failed to fetch http://cn.archive.ubuntu.com/ubuntu/dists/focal-updates/InRelease  Connection failed [IP: 91.189.91.38 80]
W: Failed to fetch http://cn.archive.ubuntu.com/ubuntu/dists/focal-backports/InRelease  Connection failed [IP: 91.189.91.39 80]
W: Failed to fetch http://security.ubuntu.com/ubuntu/dists/focal-security/InRelease  Connection failed [IP: 91.189.91.38 80]
W: Some index files failed to download. They have been ignored, or old ones used instead.

问题解决
1，修改 DNS 地址

# 修改DNS地址
sudo echo "nameserver 8.8.8.8" | sudo tee /etc/resolv.conf > /dev/null
# 可换的DNS有:
# 114公共DNS: 114.114.114.114和114.114.115.115
# 阿里的DNS: 223.5.5.5和223.6.6.6、
# 腾讯的DNS: 119.29.29.29和182.254.116.116
# 百度的DNS: 180.76.76.76
# Google的DNS: 8.8.8.8和8.8.4.4

# 测试是否修改成功:
cat /etc/resolv.conf
# 重新更新
sudo apt-get update --fix-missing

2，添加镜像

# 保险起见可以备份一下这个需要更改的文件
sudo cp /etc/apt/sources.list /etc/apt/sources.list.bak
sudo vim /etc/apt/sources.list

deb https://mirrors.ustc.edu.cn/ubuntu/ bionic main restricted universe multiverse
deb-src https://mirrors.ustc.edu.cn/ubuntu/ bionic main restricted universe multiverse
deb https://mirrors.ustc.edu.cn/ubuntu/ bionic-updates main restricted universe multiverse
deb-src https://mirrors.ustc.edu.cn/ubuntu/ bionic-updates main restricted universe multiverse
deb https://mirrors.ustc.edu.cn/ubuntu/ bionic-backports main restricted universe multiverse
deb-src https://mirrors.ustc.edu.cn/ubuntu/ bionic-backports main restricted universe multiverse
deb https://mirrors.ustc.edu.cn/ubuntu/ bionic-security main restricted universe multiverse
deb-src https://mirrors.ustc.edu.cn/ubuntu/ bionic-security main restricted universe multiverse
deb https://mirrors.ustc.edu.cn/ubuntu/ bionic-proposed main restricted universe multiverse
deb-src https://mirrors.ustc.edu.cn/ubuntu/ bionic-proposed main restricted universe multiverse

deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ xenial main restricted universe multiverse
# deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ xenial main restricted universe multiverse
deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ xenial-updates main restricted universe multiverse
# deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ xenial-updates main restricted universe multiverse
deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ xenial-backports main restricted universe multiverse
# deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ xenial-backports main restricted universe multiverse
deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ xenial-security main restricted universe multiverse
# deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ xenial-security main restricted universe multiverse

deb http://mirrors.aliyun.com/ubuntu/ trusty main multiverse restricted universe
deb http://mirrors.aliyun.com/ubuntu/ trusty-backports main multiverse restricted universe
deb http://mirrors.aliyun.com/ubuntu/ trusty-proposed main multiverse restricted universe
deb http://mirrors.aliyun.com/ubuntu/ trusty-security main multiverse restricted universe
deb http://mirrors.aliyun.com/ubuntu/ trusty-updates main multiverse restricted universe
deb-src http://mirrors.aliyun.com/ubuntu/ trusty main multiverse restricted universe
deb-src http://mirrors.aliyun.com/ubuntu/ trusty-backports main multiverse restricted universe
deb-src http://mirrors.aliyun.com/ubuntu/ trusty-proposed main multiverse restricted universe
deb-src http://mirrors.aliyun.com/ubuntu/ trusty-security main multiverse restricted universe
deb [arch=amd64] https://download.docker.com/linux/ubuntu xenial stable
# deb-src [arch=amd64] https://download.docker.com/linux/ubuntu xenial stable
# deb-src [arch=amd64] https://download.docker.com/linux/ubuntu xenial stable
deb-src http://mirrors.aliyun.com/ubuntu/ trusty-updates main multiverse restricted universe
# deb-src [arch=amd64] https://download.docker.com/linux/ubuntu xenial stable