我的 Ubuntu 14.04 LTS 出现问题，当我运行“apt-get update”时，显示一条错误消息：E：部分索引文件下载失败。它们已被忽略或使用旧文件代替。
Ign http://mirrors.melbourne.co.uk trusty InRelease
Hit http://security.ubuntu.com trusty-security InRelease
Get:1 http://ppa.launchpad.net trusty InRelease [15.5 kB]
Hit http://mirrors.melbourne.co.uk trusty-updates InRelease
Hit http://security.ubuntu.com trusty-security/main amd64 Packages
Hit http://mirrors.melbourne.co.uk trusty Release.gpg
Hit http://security.ubuntu.com trusty-security/restricted amd64 Packages
Hit http://mirrors.melbourne.co.uk trusty-updates/main amd64 Packages
Hit http://security.ubuntu.com trusty-security/main i386 Packages
Hit http://ppa.launchpad.net trusty InRelease
Hit http://mirrors.melbourne.co.uk trusty-updates/restricted amd64 Packages
Hit http://security.ubuntu.com trusty-security/restricted i386 Packages
Hit http://mirrors.melbourne.co.uk trusty-updates/main i386 Packages
Hit http://security.ubuntu.com trusty-security/main Translation-en
Ign https://ubuntu.mirror.tn trusty InRelease
Get:2 http://ppa.launchpad.net trusty/main amd64 Packages [3,396 B]
Hit http://mirrors.melbourne.co.uk trusty-updates/restricted i386 Packages
Ign https://ubuntu.mirror.tn trusty-updates InRelease
Hit http://security.ubuntu.com trusty-security/restricted Translation-en
Ign https://ubuntu.mirror.tn trusty-backports InRelease
Hit http://mirrors.melbourne.co.uk trusty-updates/main Translation-en
Ign https://extras.ubuntu.com trusty InRelease
Ign https://ubuntu.mirror.tn trusty-security InRelease
Get:3 http://ppa.launchpad.net trusty/main i386 Packages [3,396 B]
Ign https://ubuntu.mirror.tn trusty Release.gpg
Hit http://mirrors.melbourne.co.uk trusty-updates/restricted Translation-en
Ign https://ubuntu.mirror.tn trusty-updates Release.gpg
Ign https://ubuntu.mirror.tn trusty-backports Release.gpg
Hit http://mirrors.melbourne.co.uk trusty Release
Ign https://extras.ubuntu.com trusty Release.gpg
Ign https://ubuntu.mirror.tn trusty-security Release.gpg
Get:4 http://ppa.launchpad.net trusty/main Translation-en [1,556 B]
Ign https://ubuntu.mirror.tn trusty Release
Hit http://mirrors.melbourne.co.uk trusty/main amd64 Packages
Ign https://ubuntu.mirror.tn trusty-updates Release
Ign https://ubuntu.mirror.tn trusty-backports Release
Hit http://mirrors.melbourne.co.uk trusty/restricted amd64 Packages
Get:5 https://cran.rstudio.com trusty/ InRelease
Ign https://cran.rstudio.com trusty/ InRelease
Ign https://ubuntu.mirror.tn trusty-security Release
Ign https://extras.ubuntu.com trusty Release
Hit http://mirrors.melbourne.co.uk trusty/main i386 Packages
Hit https://cran.rstudio.com trusty/ Release.gpg
Hit http://mirrors.melbourne.co.uk trusty/restricted i386 Packages
Hit https://cran.rstudio.com trusty/ Release
Hit http://ppa.launchpad.net trusty/main amd64 Packages
Hit https://cran.rstudio.com trusty/ Packages
Hit http://mirrors.melbourne.co.uk trusty/main Translation-en
Hit http://ppa.launchpad.net trusty/main i386 Packages
Get:6 https://cran.rstudio.com trusty/ Translation-en_US
Hit http://mirrors.melbourne.co.uk trusty/restricted Translation-en
Hit http://ppa.launchpad.net trusty/main Translation-en
Get:7 https://linux.dropbox.com trusty InRelease
Ign https://linux.dropbox.com trusty InRelease
Ign https://ppa.launchpad.net trusty InRelease
Ign http://mirrors.melbourne.co.uk trusty/main Translation-en_US
Hit https://linux.dropbox.com trusty Release.gpg
Ign http://mirrors.melbourne.co.uk trusty/restricted Translation-en_US
Hit https://linux.dropbox.com trusty Release
Hit https://linux.dropbox.com trusty/main amd64 Packages
Hit https://linux.dropbox.com trusty/main i386 Packages
Ign https://cran.rstudio.com trusty/ Translation-en_US
Ign https://ppa.launchpad.net trusty Release.gpg
Ign https://cran.rstudio.com trusty/ Translation-en
Ign https://ppa.launchpad.net trusty Release
Ign https://ppa.launchpad.net trusty/main amd64 Packages/DiffIndex
Ign https://ppa.launchpad.net trusty/main i386 Packages/DiffIndex
Ign https://linux.dropbox.com trusty/main Translation-en_US
Ign https://linux.dropbox.com trusty/main Translation-en
Err https://extras.ubuntu.com trusty/main amd64 Packages
gnutls_handshake() failed: An unexpected TLS packet was received.
Err https://extras.ubuntu.com trusty/main i386 Packages
gnutls_handshake() failed: An unexpected TLS packet was received.
Ign https://extras.ubuntu.com trusty/main Translation-en_US
Ign https://extras.ubuntu.com trusty/main Translation-en
Err https://ubuntu.mirror.tn trusty/multiverse amd64 Packages
Failed to connect to ubuntu.mirror.tn port 443: Connection refused
Err https://ubuntu.mirror.tn trusty/multiverse i386 Packages
Failed to connect to ubuntu.mirror.tn port 443: Connection refused
Ign https://ubuntu.mirror.tn trusty/multiverse Translation-en_US
Ign https://ubuntu.mirror.tn trusty/multiverse Translation-en
Err https://ubuntu.mirror.tn trusty-updates/multiverse amd64 Packages
Failed to connect to ubuntu.mirror.tn port 443: Connection refused
Err https://ubuntu.mirror.tn trusty-updates/multiverse i386 Packages
Failed to connect to ubuntu.mirror.tn port 443: Connection refused
Ign https://ubuntu.mirror.tn trusty-updates/multiverse Translation-en_US
Ign https://ubuntu.mirror.tn trusty-updates/multiverse Translation-en
Err https://ubuntu.mirror.tn trusty-backports/main amd64 Packages
Failed to connect to ubuntu.mirror.tn port 443: Connection refused
Err https://ubuntu.mirror.tn trusty-backports/restricted amd64 Packages
Failed to connect to ubuntu.mirror.tn port 443: Connection refused
Err https://ubuntu.mirror.tn trusty-backports/universe amd64 Packages
Failed to connect to ubuntu.mirror.tn port 443: Connection refused
Err https://ubuntu.mirror.tn trusty-backports/multiverse amd64 Packages
Failed to connect to ubuntu.mirror.tn port 443: Connection refused
Err https://ubuntu.mirror.tn trusty-backports/main i386 Packages
Failed to connect to ubuntu.mirror.tn port 443: Connection refused
Err https://ubuntu.mirror.tn trusty-backports/restricted i386 Packages
Failed to connect to ubuntu.mirror.tn port 443: Connection refused
Err https://ubuntu.mirror.tn trusty-backports/universe i386 Packages
Failed to connect to ubuntu.mirror.tn port 443: Connection refused
Err https://ubuntu.mirror.tn trusty-backports/multiverse i386 Packages
Failed to connect to ubuntu.mirror.tn port 443: Connection refused
Ign https://ubuntu.mirror.tn trusty-backports/main Translation-en_US
Ign https://ubuntu.mirror.tn trusty-backports/main Translation-en
Ign https://ubuntu.mirror.tn trusty-backports/multiverse Translation-en_US
Ign https://ubuntu.mirror.tn trusty-backports/multiverse Translation-en
Ign https://ubuntu.mirror.tn trusty-backports/restricted Translation-en_US
Ign https://ubuntu.mirror.tn trusty-backports/restricted Translation-en
Ign https://ubuntu.mirror.tn trusty-backports/universe Translation-en_US
Ign https://ubuntu.mirror.tn trusty-backports/universe Translation-en
Err https://ubuntu.mirror.tn trusty-security/main amd64 Packages
Failed to connect to ubuntu.mirror.tn port 443: Connection refused
Err https://ubuntu.mirror.tn trusty-security/restricted amd64 Packages
Failed to connect to ubuntu.mirror.tn port 443: Connection refused
Err https://ubuntu.mirror.tn trusty-security/universe amd64 Packages
Failed to connect to ubuntu.mirror.tn port 443: Connection refused
Err https://ubuntu.mirror.tn trusty-security/multiverse amd64 Packages
Failed to connect to ubuntu.mirror.tn port 443: Connection refused
Err https://ubuntu.mirror.tn trusty-security/main i386 Packages
Failed to connect to ubuntu.mirror.tn port 443: Connection refused
Err https://ubuntu.mirror.tn trusty-security/restricted i386 Packages
Failed to connect to ubuntu.mirror.tn port 443: Connection refused
Err https://ubuntu.mirror.tn trusty-security/universe i386 Packages
Failed to connect to ubuntu.mirror.tn port 443: Connection refused
Err https://ubuntu.mirror.tn trusty-security/multiverse i386 Packages
Failed to connect to ubuntu.mirror.tn port 443: Connection refused
Ign https://ubuntu.mirror.tn trusty-security/main Translation-en_US
Ign https://ubuntu.mirror.tn trusty-security/main Translation-en
Ign https://ubuntu.mirror.tn trusty-security/multiverse Translation-en_US
Ign https://ubuntu.mirror.tn trusty-security/multiverse Translation-en
Ign https://ubuntu.mirror.tn trusty-security/restricted Translation-en_US
Ign https://ubuntu.mirror.tn trusty-security/restricted Translation-en
Ign https://ubuntu.mirror.tn trusty-security/universe Translation-en_US
Ign https://ubuntu.mirror.tn trusty-security/universe Translation-en
Ign https://ppa.launchpad.net trusty/main Translation-en_US
Ign https://ppa.launchpad.net trusty/main Translation-en
Err https://ppa.launchpad.net trusty/main amd64 Packages
HttpError404
Err https://ppa.launchpad.net trusty/main i386 Packages
HttpError404
Fetched 23.8 kB in 25s (940 B/s)
W: Failed to fetch https://ubuntu.mirror.tn/dists/trusty/multiverse/binary-amd64/Packages Failed to connect to ubuntu.mirror.tn port 443: Connection refused
W: Failed to fetch https://ubuntu.mirror.tn/dists/trusty/multiverse/binary-i386/Packages Failed to connect to ubuntu.mirror.tn port 443: Connection refused
W: Failed to fetch https://ubuntu.mirror.tn/dists/trusty-updates/multiverse/binary-amd64/Packages Failed to connect to ubuntu.mirror.tn port 443: Connection refused
W: Failed to fetch https://ubuntu.mirror.tn/dists/trusty-updates/multiverse/binary-i386/Packages Failed to connect to ubuntu.mirror.tn port 443: Connection refused
W: Failed to fetch https://ubuntu.mirror.tn/dists/trusty-backports/main/binary-amd64/Packages Failed to connect to ubuntu.mirror.tn port 443: Connection refused
W: Failed to fetch https://ubuntu.mirror.tn/dists/trusty-backports/restricted/binary-amd64/Packages Failed to connect to ubuntu.mirror.tn port 443: Connection refused
W: Failed to fetch https://ubuntu.mirror.tn/dists/trusty-backports/universe/binary-amd64/Packages Failed to connect to ubuntu.mirror.tn port 443: Connection refused
W: Failed to fetch https://ubuntu.mirror.tn/dists/trusty-backports/multiverse/binary-amd64/Packages Failed to connect to ubuntu.mirror.tn port 443: Connection refused
W: Failed to fetch https://ubuntu.mirror.tn/dists/trusty-backports/main/binary-i386/Packages Failed to connect to ubuntu.mirror.tn port 443: Connection refused
W: Failed to fetch https://ubuntu.mirror.tn/dists/trusty-backports/restricted/binary-i386/Packages Failed to connect to ubuntu.mirror.tn port 443: Connection refused
W: Failed to fetch https://ubuntu.mirror.tn/dists/trusty-backports/universe/binary-i386/Packages Failed to connect to ubuntu.mirror.tn port 443: Connection refused
W: Failed to fetch https://ubuntu.mirror.tn/dists/trusty-backports/multiverse/binary-i386/Packages Failed to connect to ubuntu.mirror.tn port 443: Connection refused
W: Failed to fetch https://ubuntu.mirror.tn/dists/trusty-security/main/binary-amd64/Packages Failed to connect to ubuntu.mirror.tn port 443: Connection refused
W: Failed to fetch https://ubuntu.mirror.tn/dists/trusty-security/restricted/binary-amd64/Packages Failed to connect to ubuntu.mirror.tn port 443: Connection refused
W: Failed to fetch https://ubuntu.mirror.tn/dists/trusty-security/universe/binary-amd64/Packages Failed to connect to ubuntu.mirror.tn port 443: Connection refused
W: Failed to fetch https://ubuntu.mirror.tn/dists/trusty-security/multiverse/binary-amd64/Packages Failed to connect to ubuntu.mirror.tn port 443: Connection refused
W: Failed to fetch https://ubuntu.mirror.tn/dists/trusty-security/main/binary-i386/Packages Failed to connect to ubuntu.mirror.tn port 443: Connection refused
W: Failed to fetch https://ubuntu.mirror.tn/dists/trusty-security/restricted/binary-i386/Packages Failed to connect to ubuntu.mirror.tn port 443: Connection refused
W: Failed to fetch https://ubuntu.mirror.tn/dists/trusty-security/universe/binary-i386/Packages Failed to connect to ubuntu.mirror.tn port 443: Connection refused
W: Failed to fetch https://ubuntu.mirror.tn/dists/trusty-security/multiverse/binary-i386/Packages Failed to connect to ubuntu.mirror.tn port 443: Connection refused
W: Failed to fetch https://extras.ubuntu.com/ubuntu/dists/trusty/main/binary-amd64/Packages gnutls_handshake() failed: An unexpected TLS packet was received.
W: Failed to fetch https://extras.ubuntu.com/ubuntu/dists/trusty/main/binary-i386/Packages gnutls_handshake() failed: An unexpected TLS packet was received.
W: Failed to fetch https://ppa.launchpad.net/webupd8team/java/ubuntu/dists/trusty/main/binary-amd64/Packages HttpError404
W: Failed to fetch https://ppa.launchpad.net/webupd8team/java/ubuntu/dists/trusty/main/binary-i386/Packages HttpError404
E: Some index files failed to download. They have been ignored, or old ones used instead.
注意：我在其他论坛上找到了许多解决方案：例如：
cd /var/lib/apt/列表/
/var/lib/apt/列表$ rm -vf *
apt-get 更新
apt-get 升级
但这些命令不能解决我的问题
答案1
Tarroumi Mohamed - 您是否尝试过使用不同的互联网连接来隔离是否是路由器问题？您必须首先清除上述所有内容，以确保是路由器的问题。
还可以尝试使用相同或更新操作系统版本的 Live CD/DVD（USB 启动设备很方便，但比人们想象的更容易被感染 - 请参阅 Stuxnet 和 BadUSB）。
DNS 损坏和其他正常访问损坏（通过攻击者的代理强制路由）显然也会发生在路由器中。尤其是由于制造商的懒惰/受 NSA 贿赂等原因，路由器几乎从来都不是很安全。
注意：在安全方面，偏执是一种美德，但只能达到一定程度。然后它就和其他地方一样不健康了！您的问题可能都不是恶意的，但实际上，相同的程序可用于排除故障。