在Linode（Ubuntu 16.10）上，通过
启用UFW防火墙后sudo ufw allow OpenSSH
sudo ufw enable
sudo ufw allow in "Apache Full"
（虽然我并不完全确定防火墙设置是我的问题的根源......）
sudo apt-get update给了我以下信息：
Ign:1 http://mirrors.linode.com/ubuntu yakkety InRelease
Ign:2 http://mirrors.linode.com/ubuntu yakkety-updates InRelease
Ign:3 http://mirrors.linode.com/ubuntu yakkety-backports InRelease
Err:4 http://mirrors.linode.com/ubuntu yakkety Release
404 Not Found [IP: ****:****:*::****:**** 80]
Err:5 http://mirrors.linode.com/ubuntu yakkety-updates Release
404 Not Found [IP: ****:****:*::****:**** 80]
Err:6 http://mirrors.linode.com/ubuntu yakkety-backports Release
404 Not Found [IP: ****:****:*::****:**** 80]
Ign:7 http://security.ubuntu.com/ubuntu yakkety-security InRelease
Err:8 http://security.ubuntu.com/ubuntu yakkety-security Release
404 Not Found [IP: ****:***:****::** 80]
Reading package lists... Done
E: The repository 'http://mirrors.linode.com/ubuntu yakkety Release' does no longer 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.
E: The repository 'http://mirrors.linode.com/ubuntu yakkety-updates Release' does no longer 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.
E: The repository 'http://mirrors.linode.com/ubuntu yakkety-backports Release' does no longer 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.
E: The repository 'http://security.ubuntu.com/ubuntu yakkety-security Release' does no longer 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.
源文件/etc/apt/source.list：
# deb http://mirrors.linode.com/ubuntu/ yakkety main restricted
# deb http://mirrors.linode.com/ubuntu/ yakkety-updates main restricted
# deb http://security.ubuntu.com/ubuntu yakkety-security main restricted
# See http://help.ubuntu.com/community/UpgradeNotes for how to upgrade to
# newer versions of the distribution.
deb http://mirrors.linode.com/ubuntu/ yakkety main restricted
# deb-src http://mirrors.linode.com/ubuntu/ yakkety main restricted
## Major bug fix updates produced after the final release of the
## distribution.
deb http://mirrors.linode.com/ubuntu/ yakkety-updates main restricted
# deb-src http://mirrors.linode.com/ubuntu/ yakkety-updates main restricted
## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu
## team. Also, please note that software in universe WILL NOT receive any
## review or updates from the Ubuntu security team.
deb http://mirrors.linode.com/ubuntu/ yakkety universe
# deb-src http://mirrors.linode.com/ubuntu/ yakkety universe
deb http://mirrors.linode.com/ubuntu/ yakkety-updates universe
# deb-src http://mirrors.linode.com/ubuntu/ yakkety-updates universe
## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu
## team, and may not be under a free licence. Please satisfy yourself as to
## your rights to use the software. Also, please note that software in
## multiverse WILL NOT receive any review or updates from the Ubuntu
## security team.
deb http://mirrors.linode.com/ubuntu/ yakkety multiverse
# deb-src http://mirrors.linode.com/ubuntu/ yakkety multiverse
deb http://mirrors.linode.com/ubuntu/ yakkety-updates multiverse
# deb-src http://mirrors.linode.com/ubuntu/ yakkety-updates multiverse
## N.B. software from this repository may not have been tested as
## extensively as that contained in the main release, although it includes
## newer versions of some applications which may provide useful features.
## Also, please note that software in backports WILL NOT receive any review
## or updates from the Ubuntu security team.
deb http://mirrors.linode.com/ubuntu/ yakkety-backports main restricted universe multiverse
# deb-src http://mirrors.linode.com/ubuntu/ yakkety-backports main restricted universe multiverse
## Uncomment the following two lines to add software from Canonical's
## 'partner' repository.
## This software is not part of Ubuntu, but is offered by Canonical and the
## respective vendors as a service to Ubuntu users.
# deb http://archive.canonical.com/ubuntu yakkety partner
# deb-src http://archive.canonical.com/ubuntu yakkety partner
deb http://security.ubuntu.com/ubuntu yakkety-security main restricted
# deb-src http://security.ubuntu.com/ubuntu yakkety-security main restricted
deb http://security.ubuntu.com/ubuntu yakkety-security universe
# deb-src http://security.ubuntu.com/ubuntu yakkety-security universe
deb http://security.ubuntu.com/ubuntu yakkety-security multiverse
# deb-src http://security.ubuntu.com/ubuntu yakkety-security multiverse
我已尝试sudo apt-get dist-update无效（也有404错误）。
我还完成了unset http_proxy和unset https_proxy;
apt-get -o Acquire::ForceIPv4=true update - 使用IPv4时仍然失败
我可以ping 8.8.8.8就好了。
......没什么可行的。任何人都知道如何解决这个问题？
答案 0 :(得分：0)
Linode支持人员的回应：
看起来您正在使用已达到其生命周期状态的Ubuntu版本。
https://wiki.ubuntu.com/Releases
您可以参考以下链接，看看您是否能够以其他方式更新此链接。另一个选项是为服务器部署更新的Ubuntu映像，并将数据复制到新磁盘。
答案 1 :(得分：0)
我也被困在这上面了。但我得到了它的工作。
我必须更换＆＃34; us.archive.ubuntu.com＆＃34;和＆＃34; security.ubuntu.com＆＃34;在/etc/apt/sources.list WITH＆＃34; old-releases.ubuntu.com＆＃34;然后我就能完成下载一些软件包，比如Ayush Kumar在sudo apt-get update fail on Ubuntu 17.04中说的。
对于我的托管公司Linode列出的其他更新，我使用了以下内容：
我必须在sudo apt-get update中使用--allow-unauthenticated标志。
sudo apt-get update --allow-unauthenticated
然后我就能完成更新。