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。