[CentOS] Centos 8 two network cards

Thu Jul 15 19:55:42 UTC 2021
Valeri Galtsev <galtsev at kicp.uchicago.edu>

On 7/15/21 2:39 PM, Ken Smith via CentOS wrote:
> Hi folks, I'm a bit confused about how to set up two network cards in 
> different LANS in C8. I've done this multiple times in Centos6 and 
> lower, but in the NetworkManager/systemd world I'm all at sea without 
> any charts. (I'm sure there's a HKLM in there somewhere -sorry ;-)) and 
> my Googlefoo is failing me this evening.
> Via the GUI it will let me configure one device or the other but not 
> both :-(
> Anyway I want one NIC with IP and GW
> and the other with IP and no gateway.
> I've seen a method that removes NetworkManager and installs 
> network-scripts then configures the ifcfg-eth0 and ifcfg-eth1 scripts. 
> Interestingly the devices seem to be still called eth0 & 1 on this 
> system which happens to be a VM. When I use this method the systemctl 
> start network appears not to be able to find eth1.
> Is there a recommended way to do this? I'd prefer to use 'approved' 
> techniques rather than work arounds.
> Any suggestions?

This is for Debian, but it must be the same in CentOS. Being in Debian a 
"beginner" who fled CentOS, this one operation (configuring second 
network card) is the last only operation which I still use GUI for, not 
command line tools or Better editing config files...

Start network manager editor (on Debian the command is: 

Click Ethernet

click "+" choose "Ethernet" as connection type.

change name of new connection to "Wired connection 2"

and configure all parameters, make sure you choose correct ethernet 
adapter in one of dro-downs.

I hope, this helps.


> Thanks
> Ken

Valeri Galtsev
Sr System Administrator
Department of Astronomy and Astrophysics
Kavli Institute for Cosmological Physics
University of Chicago
Phone: 773-702-4247