在更新debian11的时候发现个了更新出错的问题，主要是404 Not Found [IP: 151.101.26.132 80]、E: The repository 'http://security.debian.org bullseye/updates Release' does not have a Release file.一般来说是系统自带的source.list里面的链接是错误的，可能是从低版本升级上来的；解决办法就更换下源链接即可了。
root@zhujiceping:~# apt update
Hit:1 http://deb.debian.org/debian bullseye InRelease
Hit:2 http://deb.debian.org/debian bullseye-updates InRelease
Hit:3 http://deb.debian.org/debian bullseye-backports InRelease
Ign:4 http://security.debian.org bullseye/updates InRelease
Err:5 http://security.debian.org bullseye/updates Release
404 Not Found [IP: 151.101.26.132 80]
Reading package lists... Done
E: The repository 'http://security.debian.org bullseye/updates Release' does not have a Release file.
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.
问题出在上面的源链接上，链接变了，换成这样：
debhttp://deb.debian.org/debian bullseye main
deb http://deb.debian.org/debian-security/ bullseye-security main
deb http://deb.debian.org/debian bullseye-updates main
请修改下源(/etc/apt/source.list)，替换成下面的吧：
deb http://mirrors.linode.com/debian bullseye main
deb-src http://mirrors.linode.com/debian bullseye main
deb http://mirrors.linode.com/debian-security/ bullseye-security main
deb-src http://mirrors.linode.com/debian-security/ bullseye-security main
deb http://mirrors.linode.com/debian bullseye-updates main
deb-src http://mirrors.linode.com/debian bullseye-updates main
如果是国内的机器建议切换阿里、腾讯、163等，只需要将mirrors.linode.com改为下面对应的你需要的源即可！
中科大：mirrors.ustc.edu.cn
清华：mirrors.tuna.tsinghua.edu.cn
阿里：mirrors.aliyun.com
腾讯：mirrors.tencent.com
网易：mirrors.163.com
华为：mirrors.huaweicloud.com