解决unable unable to locate package问题

禁用ipv6：
sudo vi /etc/sysctl.conf

添加：

net.ipv6.conf.all.disable_ipv6 = 1
net.ipv6.conf.default.disable_ipv6 = 1
net.ipv6.conf.lo.disable_ipv6 = 1
net.ipv6.conf.eth0.disable_ipv6 = 1
 保存退出   

sudo sysctl -p 最后用：ip a | grep inet6验证，如没有任何输出则禁用成功！或者用ifconfig看有没有ipv6. 更换dns：

路径:/etc/resolv.conf

# Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8)
#     DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN
nameserver 202.38.193.33#你的dns
nameserver 127.0.0.1
search lan

路径：/etc/network/interfaces

# interfaces(5) file used by ifup(8) and ifdown(8)
auto lo
iface lo inet loopback

# The primary network interface
auto eth0
iface eth0 inet static
address 192.168.1.166
netmask 255.255.255.0
gateway 192.168.1.1
dns-nameserver 127.0.0.1
dns-nameservers 202.38.193.33#你的dns

路径：/etc/resolvconf/resolv.conf.d/base

nameserver 127.0.0.1
nameserver 202.38.193.33

路径：/etc/NetworkManager/NetworkManager.conf

[main]
plugins=ifupdown,keyfile
dns=dnsmasq

[ifupdown]
managed=true

更换源：

路径：/etc/apt/source.list

#中国科技大学
 
deb http://debian.ustc.edu.cn/ubuntu/ precise main restricted universe multiverse
deb http://debian.ustc.edu.cn/ubuntu/ precise-backports restricted universe multiverse
deb http://debian.ustc.edu.cn/ubuntu/ precise-proposed main restricted universe multiverse
deb http://debian.ustc.edu.cn/ubuntu/ precise-security main restricted universe multiverse
deb http://debian.ustc.edu.cn/ubuntu/ precise-updates main restricted universe multiverse
deb-src http://debian.ustc.edu.cn/ubuntu/ precise main restricted universe multiverse
deb-src http://debian.ustc.edu.cn/ubuntu/ precise-backports main restricted universe multiverse
deb-src http://debian.ustc.edu.cn/ubuntu/ precise-proposed main restricted universe multiverse
deb-src http://debian.ustc.edu.cn/ubuntu/ precise-security main restricted universe multiverse
deb-src http://debian.ustc.edu.cn/ubuntu/ precise-updates main restricted universe multiverse
 

apt-get update更新就可以了

转载自：http://www.ithao123.cn/content-2717974.html

转载自：http://www.07net01.com/linux/ubuntu12_04_jinyong_ipv6_11583_1346037862.html

转载自：http://www.myhack58.com/Article/48/66/2015/61855.htm