Start the machine and edit as below

Adapter 1=

Adapter 2 =

Adapter 3= for internet access put dns server as 8.8.8.8

Now check /etc/resolv.conf it should look like this. if 127.0.0.1 is not on the top order edit the file to look like this. then lock the file.

[root@ol7-121-rac1 ~]# cat /etc/resolv.conf
# Generated by NetworkManager
search localdomain
nameserver 127.0.0.1
nameserver 192.168.189.1
nameserver 8.8.8.8
[root@ol7-121-rac1 ~]# chattr +i /etc/resolv.conf
[root@ol7-121-rac1 ~]#
[root@ol7-121-rac1 ~]# ping google.com
PING google.com (216.58.199.142) 56(84) bytes of data.
64 bytes from bom07s01-in-f14.1e100.net (216.58.199.142): icmp_seq=1 ttl=53 time=84.8 ms
64 bytes from bom07s01-in-f14.1e100.net (216.58.199.142): icmp_seq=2 ttl=53 time=118 ms
^C
[root@ol7-121-rac1 ~]# nslookup ol7-121-scan
Server: 127.0.0.1
Address: 127.0.0.1#53
Name: ol7-121-scan.localdomain
Address: 192.168.189.107
Name: ol7-121-scan.localdomain
Address: 192.168.189.105
Name: ol7-121-scan.localdomain
Address: 192.168.189.106
[root@ol7-121-rac1 ~]# nslookup ol7-121-rac1
Server: 127.0.0.1
Address: 127.0.0.1#53
Name: ol7-121-rac1.localdomain
Address: 192.168.189.101