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CentOS yum error 14: PCYURL ERROR 7 – “Failed to connect to 2a02:2498:1:3d:5054:ff:fed3:e9

December 17, 2013 at 8:50 am Leave a comment

Dear Folks

When you are trying to update the system with yum , you may come with the above error , In which the yum tool is trying to resolve the mirrorlist url’s via IPv6 Address.

What happens here is that when the yum is unable to resolve and reach the IPv4 address it end up trying the IPv6.

Hence if you face the similar issue , I would advice you to go through the below steps and identify the real cause.

Step 1 –  Check whether you could resolve the URL  (mirrorlist.centos.org) via nslookup or dig and get an IPV6 address.

If  you fail at the above step check for the DNS configurations in /etc/resolv.conf

Step 2 –   Check with the firewall team that they have allowed the ports 80 , 443 ,21   from the linux server.

In my case it was the firewall blockage.

I have been googling  regarding the same issue and found out that several articles pointing to IPV6   saying that to disable it. Hence you could try that as a  last resort , if the above steps did not succeed.

– edit  the  /etc/sysconfig/network and the /etc/sysconfig/network-scripts/ifcfg-eth* files  to  disable any entries pointing to IPv6

– edit /etc/sysctl.conf and put the below entries and reboot the server

net.ipv6.conf.all.disable_ipv6 = 1
net.ipv6.conf.default.disable_ipv6 =

– disable the ip6tables.

Good Luck

Entry filed under: Linux. Tags: centos, yum error, yum ipv6.