This error appears when attempting to use the yum command.
[john.doe@server1 ~]# yum install example . . . One of the configured repositories failed (Unknown) . . .
This error will appear if you are unable to communicate with computers in other networks. If you are unable to ping computers in other networks, this implies some issue with your IP configuration or default gateway.
[john.doe@server1 ~]# ping -cf www.google.com . . . 4 packets transmitted, 0 received, 100% packet loss, time 2999ms
If you are able to communicate with computers in other networks, there may be some problem with the DNS servers you are using. Ensure the name servers in your /etc/resolv.conf file are able to resolve a hostname to an IP address.
[root@server1 ~]# cat /etc/resolv.conf nameserver 18.104.22.168 nameserver 22.214.171.124
If your system is using DHCP to lease IP configuration information from a DHCP server, use the dhclient command to renew your IP configuraiton information.
[john.doe@client1 ~]# sudo dhclient eth0
The base URL is found in the The content of the file /etc/yum.repos.d/CentOS-Base.repo file. Ensure the mirrorlist site is accessible.
[root@localhost ~]# cat /etc/yum.repos.d/CentOS-Base.repo . . . [base] name=CentOS-$releasever - Base mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=os&infra=$infra . . .