可用的国内源
由阿里云提供的 Debian 镜像源：
deb https://mirrors.aliyun.com/debian/ bullseye main non-free contrib
deb-src https://mirrors.aliyun.com/debian/ bullseye main non-free contrib
deb https://mirrors.aliyun.com/debian-security/ bullseye-security main
deb-src https://mirrors.aliyun.com/debian-security/ bullseye-security main
deb https://mirrors.aliyun.com/debian/ bullseye-updates main non-free contrib
deb-src https://mirrors.aliyun.com/debian/ bullseye-updates main non-free contrib
deb https://mirrors.aliyun.com/debian/ bullseye-backports main non-free contrib
deb-src https://mirrors.aliyun.com/debian/ bullseye-backports main non-free contrib由腾讯提供的 Debian 镜像源：
deb https://mirrors.tencent.com/debian/ bullseye main non-free contrib
deb-src https://mirrors.tencent.com/debian/ bullseye main non-free contrib
deb https://mirrors.tencent.com/debian-security/ bullseye-security main
deb-src https://mirrors.tencent.com/debian-security/ bullseye-security main
deb https://mirrors.tencent.com/debian/ bullseye-updates main non-free contrib
deb-src https://mirrors.tencent.com/debian/ bullseye-updates main non-free contrib
deb https://mirrors.tencent.com/debian/ bullseye-backports main non-free contrib
deb-src https://mirrors.tencent.com/debian/ bullseye-backports main non-free contrib由北京清华大学提供的 Debian 镜像源：
deb https://mirrors.tuna.tsinghua.edu.cn/debian/ bullseye main contrib non-free
deb-src https://mirrors.tuna.tsinghua.edu.cn/debian/ bullseye main contrib non-free
deb https://mirrors.tuna.tsinghua.edu.cn/debian/ bullseye-updates main contrib non-free
deb-src https://mirrors.tuna.tsinghua.edu.cn/debian/ bullseye-updates main contrib non-free
deb https://mirrors.tuna.tsinghua.edu.cn/debian/ bullseye-backports main contrib non-free
deb-src https://mirrors.tuna.tsinghua.edu.cn/debian/ bullseye-backports main contrib non-free
deb https://mirrors.tuna.tsinghua.edu.cn/debian-security bullseye-security main contrib non-free
deb-src https://mirrors.tuna.tsinghua.edu.cn/debian-security bullseye-security main contrib non-free由中国科学技术大学提供的 Debian 镜像源：
deb http://mirrors.ustc.edu.cn/debian bullseye main contrib non-free
deb-src http://mirrors.ustc.edu.cn/debian bullseye main contrib non-free
deb http://mirrors.ustc.edu.cn/debian bullseye-updates main contrib non-free
deb-src http://mirrors.ustc.edu.cn/debian bullseye-updates main contrib non-free
deb http://mirrors.ustc.edu.cn/debian bullseye-proposed-updates main contrib non-free
deb-src http://mirrors.ustc.edu.cn/debian bullseye-proposed-updates main contrib non-free由上海交通大学提供的 Debian 镜像源：
deb http://mirrors.sjtu.edu.cn/debian bullseye main contrib non-free
deb-src http://mirrors.sjtu.edu.cn/debian bullseye main contrib non-free
deb http://mirrors.sjtu.edu.cn/debian bullseye-updates main contrib non-free
deb-src http://mirrors.sjtu.edu.cn/debian bullseye-updates main contrib non-free
deb http://mirrors.sjtu.edu.cn/debian bullseye-proposed-updates main contrib non-free
deb-src http://mirrors.sjtu.edu.cn/debian bullseye-proposed-updates main contrib non-free由北京外国语大学提供的 Debian 镜像源：
deb https://mirrors.bfsu.edu.cn/debian/ bullseye main contrib non-free
deb-src https://mirrors.bfsu.edu.cn/debian/ bullseye main contrib non-free
deb https://mirrors.bfsu.edu.cn/debian/ bullseye-updates main contrib non-free
deb-src https://mirrors.bfsu.edu.cn/debian/ bullseye-updates main contrib non-free
deb https://mirrors.bfsu.edu.cn/debian/ bullseye-backports main contrib non-free
deb-src https://mirrors.bfsu.edu.cn/debian/ bullseye-backports main contrib non-free
deb https://mirrors.bfsu.edu.cn/debian-security bullseye-security main contrib non-free
deb-src https://mirrors.bfsu.edu.cn/debian-security bullseye-security main contrib non-free由华为提供的 Deiban 镜像源：
deb https://mirrors.huaweicloud.com/debian/ bullseye main non-free contrib
deb-src https://mirrors.huaweicloud.com/debian/ bullseye main non-free contrib
deb https://mirrors.huaweicloud.com/debian-security/ bullseye-security main
deb-src https://mirrors.huaweicloud.com/debian-security/ bullseye-security main
deb https://mirrors.huaweicloud.com/debian/ bullseye-updates main non-free contrib
deb-src https://mirrors.huaweicloud.com/debian/ bullseye-updates main non-free contrib
deb https://mirrors.huaweicloud.com/debian/ bullseye-backports main non-free contrib
deb-src https://mirrors.huaweicloud.com/debian/ bullseye-backports main non-free contrib由网易提供的 Debian 镜像源：
deb https://mirrors.163.com/debian/ bullseye main non-free contrib
deb-src https://mirrors.163.com/debian/ bullseye main non-free contrib
deb https://mirrors.163.com/debian-security/ bullseye-security main
deb-src https://mirrors.163.com/debian-security/ bullseye-security main
deb https://mirrors.163.com/debian/ bullseye-updates main non-free contrib
deb-src https://mirrors.163.com/debian/ bullseye-updates main non-free contrib
deb https://mirrors.163.com/debian/ bullseye-backports main non-free contrib
deb-src https://mirrors.163.com/debian/ bullseye-backports main non-free contrib手动更换镜像源
手动更换 Debian 镜像源配置主要分为以下三步：
- 用熟悉的文本编辑器打开
/etc/apt/sources.list文件（需要sudo权限），或是直接执行sudo apt edit-sources命令。 - 替换文件内容为上面任意一个镜像站的源配置代码并保存。
- 运行
sudo apt-get update命令更新软件索引。
命令更换镜像源
使用命令替换镜像源更为快捷。比如在没有更换过数据源的情况下，要使用阿里云的 Debian 镜像源：
sudo sed -i 's/deb.debian.org/mirrors.aliyun.com/g' /etc/apt/sources.list这样就完成了默认源到阿里云镜像源的配置。接下来同样需要执行一下 sudo apt-get update 命令更新软件索引。
上面这个命令的原理在镜像源的地址上。不同的镜像源通常只是域名有所区别，其他部分大致类似。所以之需要通过 sed 命令来修改 /etc/apt/sources.list 这个源配置文件中的域名地址就足够了。
但这意味着使用这个命令方式修改镜像源的配置时需要格外注意。如果输入的匹配地址或替换地址有误，有可能不会生效，或是导致镜像源异常。遇到这种情况，可以选择上面手动更换镜像源的方式来解决。
我们可以看到使用的是https协议
问题描述
然而修改好配置时，进行sudo apt-get update报错：
Reading package lists... Done
W: https://mirrors.aliyun.com/debian/dists/bullseye/InRelease: No system certificates available. Try installing ca-certificates.
W: https://mirrors.aliyun.com/debian/dists/bullseye-updates/InRelease: No system certificates available. Try installing ca-certificates.
W: Failed to fetch https://mirrors.aliyun.com/debian/dists/bullseye/InRelease Certificate verification failed: The certificate is NOT trusted. The certificate issuer is unknown. Could not handshake: Error in the certificate verification.
W: Failed to fetch https://mirrors.aliyun.com/debian/dists/bullseye-updates/InRelease Certificate verification failed: The certificate is NOT trusted. The certificate issuer is unknown. Could not handshake: Error in the certificate verification.
W: Some index files failed to download. They have been ignored, or old ones used instead.
出现安全证书不信任的问题
解决办法
有三种解决办法，使用其一即可。
- 把
https协议换成http协议 - 先安装certificate库（安装命令为
sudo apt install ca-certificates），再修改成阿里云的源地址。有一种不配源怎么安装，不安装怎么配源的死锁感? - 使用中科大的源，因为他们在这使用的是
http协议。