[CentOS] New CentOS7 Install Yum will not work

Wed Dec 5 18:48:14 UTC 2018
Ed Morrison <edward.morrison at gmail.com>

Hi Everyone:

I have been fighting this all morning.  I did a new (several) installs of
CentOS7.  Yum will not update the system.  I have disabled ipv6, set
yum.conf to use IPv4 only, disabled firewalld, disabled selinux, used both
static ip and dhcp for network connectivity.  I can ping any where on the
Internet, including the mirrors, DNS works and ensured the base URL line
was uncommented.  Any help would be appreciated.

Thanks,
Ed

This is the latest error I am seeing:
[root at localhost ~]# yum check-update
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
Could not retrieve mirrorlist
http://mirrorlist.centos.org/?release=7&arch=x86_64&repo=os&infra=stock
error was
14: curl#7 - "Failed connect to mirrorlist.centos.org:80; Operation now in
progress"
Could not retrieve mirrorlist
http://mirrorlist.centos.org/?release=7&arch=x86_64&repo=extras&infra=stock
error was
14: curl#7 - "Failed connect to mirrorlist.centos.org:80; Operation now in
progress"


 One of the configured repositories failed (Unknown),
 and yum doesn't have enough cached data to continue. At this point the only
 safe thing yum can do is fail. There are a few ways to work "fix" this:

     1. Contact the upstream for the repository and get them to fix the
problem.

     2. Reconfigure the baseurl/etc. for the repository, to point to a
working
        upstream. This is most often useful if you are using a newer
        distribution release than is supported by the repository (and the
        packages for the previous distribution release still work).

     3. Run the command with the repository temporarily disabled
            yum --disablerepo=<repoid> ...

     4. Disable the repository permanently, so yum won't use it by default.
Yum
        will then just ignore the repository until you permanently enable it
        again or use --enablerepo for temporary usage:

            yum-config-manager --disable <repoid>
        or
            subscription-manager repos --disable=<repoid>

     5. Configure the failing repository to be skipped, if it is
unavailable.
        Note that yum will try to contact the repo. when it runs most
commands,
        so will have to try and fail each time (and thus. yum will be be
much
        slower). If it is a very temporary problem though, this is often a
nice
        compromise:

            yum-config-manager --save
--setopt=<repoid>.skip_if_unavailable=true

Cannot find a valid baseurl for repo: extras/7/x86_64