使用yum安装应用程序时候，报错：[Errno 14] PYCURL ERROR 7 - "Failed to connect to 2001:da8:8000:6023::230: 网络不可达"
1、系统环境
- 物理机：
Windows 7（32位）旗舰版 - 虚拟机：
CentOS 6.5
2、问题描述
从安装好系统之后，用yum源安装软件，一直可以用，今天突然就报了如下的错误，yum也无法使用了：
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
* base: mirrors.cqu.edu.cn
* extras: mirrors.tuna.tsinghua.edu.cn
* updates: mirrors.tuna.tsinghua.edu.cn
http://mirrors.cqu.edu.cn/CentOS/6.8/os/i386/repodata/repomd.xml: [Errno 14] PYCURL ERROR 7 - "couldn't connect to host"
Trying other mirror.
http://mirror.bit.edu.cn/centos/6.8/os/i386/repodata/repomd.xml: [Errno 14] PYCURL ERROR 7 - "Failed to connect to 2001:da8:204:2001:250:56ff:fea1:22: 网络不可达"
Trying other mirror.
http://mirror.lzu.edu.cn/centos/6.8/os/i386/repodata/repomd.xml: [Errno 14] PYCURL ERROR 7 - "Failed to connect to 2001:da8:c000::160: 网络不可达"
Trying other mirror.
http://mirrors.nwsuaf.edu.cn/centos/6.8/os/i386/repodata/repomd.xml: [Errno 14] PYCURL ERROR 7 - "couldn't connect to host"
Trying other mirror.
http://mirrors.neusoft.edu.cn/centos/6.8/os/i386/repodata/repomd.xml: [Errno 14] PYCURL ERROR 7 - "Failed to connect to 2001:da8:a807::25: 网络不可达"
Trying other mirror.
http://ftp.sjtu.edu.cn/centos/6.8/os/i386/repodata/repomd.xml: [Errno 14] PYCURL ERROR 7 - "Failed to connect to 2001:da8:8000:6023::230: 网络不可达"
Trying other mirror.
http://centos.ustc.edu.cn/centos/6.8/os/i386/repodata/repomd.xml: [Errno 14] PYCURL ERROR 7 - "Failed to connect to 2001:da8:d800:95::102: 网络不可达"
Trying other mirror.
http://mirrors.aliyun.com/centos/6.8/os/i386/repodata/repomd.xml: [Errno 14] PYCURL ERROR 7 - "couldn't connect to host"
Trying other mirror.
http://mirrors.163.com/centos/6.8/os/i386/repodata/repomd.xml: [Errno 14] PYCURL ERROR 7 - "couldn't connect to host"
Trying other mirror.
http://mirrors.yun-idc.com/centos/6.8/os/i386/repodata/repomd.xml: [Errno 14] PYCURL ERROR 7 - "couldn't connect to host"
Trying other mirror.
http://mirrors.aliyun.com/epel/6/i386/repodata/repomd.xml: [Errno 14] PYCURL ERROR 7 - "couldn't connect to host"
Trying other mirror.
http://mirrors.tuna.tsinghua.edu.cn/centos/6.8/extras/i386/repodata/repomd.xml: [Errno 14] PYCURL ERROR 7 - "Failed to connect to 2402:f000:1:416:166:111:206:178: 网络不可达"
Trying other mirror.
http://mirrors.cqu.edu.cn/CentOS/6.8/extras/i386/repodata/repomd.xml: [Errno 14] PYCURL ERROR 7 - "couldn't connect to host"
Trying other mirror.
http://mirror.bit.edu.cn/centos/6.8/extras/i386/repodata/repomd.xml: [Errno 14] PYCURL ERROR 7 - "Failed to connect to 2001:da8:204:2001:250:56ff:fea1:22: 网络不可达"
Trying other mirror.
http://mirror.lzu.edu.cn/centos/6.8/extras/i386/repodata/repomd.xml: [Errno 14] PYCURL ERROR 7 - "Failed to connect to 2001:da8:c000::160: 网络不可达"
Trying other mirror.
http://mirrors.nwsuaf.edu.cn/centos/6.8/extras/i386/repodata/repomd.xml: [Errno 14] PYCURL ERROR 7 - "couldn't connect to host"
Trying other mirror.
http://mirrors.zju.edu.cn/centos/6.8/extras/i386/repodata/repomd.xml: [Errno 14] PYCURL ERROR 7 - "Failed to connect to 2001:da8:e000:1410:216:3eff:fe75:6c73: 网络不可达"
Trying other mirror.
3、解决方法
3.1原因
我们来查看一下，当前用来上网的网卡eth1的信息：
[root@promote ~]# ifconfig eth1
eth1 Link encap:Ethernet HWaddr 00:0C:29:D4:EA:E2
inet addr:192.168.1.115 Bcast:255.255.255.255 Mask:255.255.255.0
inet6 addr: fe80::20c:29ff:fed4:eae2/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:4599 errors:0 dropped:0 overruns:0 frame:0
TX packets:2628 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:575396 (561.9 KiB) TX bytes:278925 (272.3 KiB)
Interrupt:19 Base address:0x2000
我们清楚地看见了inet6 addr: fe80::20c:29ff:fed4:eae2/64 Scope:Link,这一行信息，这个正是影响我们使用yum的罪魁祸首！！！下面我们就来关闭网卡的IPV6。
3.2临时解决方法
临时关闭网卡的IPV6，并重启网络服务：
[root@promote ~]# echo 1 > /proc/sys/net/ipv6/conf/all/disable_ipv6
[root@promote ~]# echo 1 > /proc/sys/net/ipv6/conf/default/disable_ipv6
[root@promote ~]# service network restart
正在关闭接口 eth1： [确定]
关闭环回接口： [确定]
弹出环回接口： [确定]
弹出界面 eth1：
正在决定 eth1 的 IP 信息...完成。
[确定]
此时，再查看网卡eth1的信息：
[root@promote ~]# ifconfig eth1
eth1 Link encap:Ethernet HWaddr 00:0C:29:D4:EA:E2
inet addr:192.168.1.115 Bcast:255.255.255.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:5563 errors:0 dropped:0 overruns:0 frame:0
TX packets:3388 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:676945 (661.0 KiB) TX bytes:414358 (404.6 KiB)
Interrupt:19 Base address:0x2000
没错，我们发现inet6 addr: fe80::20c:29ff:fed4:eae2/64 Scope:Link这一行信息没有了，此时yum就可以正常使用了；
3.3永久生效方法
需要在文件/etc/sysctl.conf中，添加如下的内容：
#shutdown IPv6
net.ipv6.conf.all.disable_ipv6 = 1
net.ipv6.conf.default.disable_ipv6 = 1
4、结语
至此，我们已经解决了这次遇到的问题，能够继续通过yum便捷地安装卸载应用程序了。
