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.

update_error_1What 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: , , .

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