CentOS - Jan 2018 - Bug in gnome-control-center and network edit module in Centos 7.4

Everyone,

I have been having a problem in setting up gateway/routers with Centos
7.4 machine and finally figured out the problem today.  I am not sure
if this bug occurred first in 7.3 but it is definitely in 7.4.  I have
other gateway routers that were created at the beginning of the Centos
7 that have been working perfectly even through the upgrades to 7.3 and
7.4, but the new gateways I have created would not work.

It seems simple now that I have the solution, but it took me an
embarrassingly too long a time to debug and resolves the problem.

The problem appears to me to be a bug in the new gnome-command-center
when using the network module to add or edit network interfaces.  The
problem that I identified is that the network module requires the user
to enter a gateway ip address even on the internal networks.  Normally
the gateway ip address is left blank on the internal interfaces, and is
only filled in on the external interface.

I was never able to get the gui using the network editor within the
gnome-control-center to be able to remove the gateway ip address from
the; internal interfaces; I was forced to enter something, and I
entered the external gateway ip address.  However, to bypass and fix
this problem, the gateway ip address is easily removed by editing the
appropriate file or files in :

/etc/sysconfig/network-scripts/ifcfg-emp3s0
/etc/sysconfig/network-scripts/ifcfg-emp4s0

The network editor in the gnome-control-center module required the
entry of a gateway ip address.  I had entered the gateway for the
external ip address in this field, and all I did to solve the problem
is to delete "GATEWAY=x.x.x.x" from both of the above files.

This allowed both of the new gateway machines I have recently created
to work like they should.

Hope this saves someone else some time.


Greg