Hello Everyone.
Thanks to all reading my query and taking out your precious time to comment.
So, I have the below setup and trying to setup a home lab using Vmware Workstation. 
 Lab_Topology
Lab_Topology
 
What do I have?
1) Windows 10  Home basic - Host OS
2) 16 GB total RAM, assigned 6 GB to Gaia R80.20
3) Tried the same setup on Vmware Workstation 14 & 15.5 version..
4) Two routers R1 & R2 with vyatta image.
 
After doing installation, defining routers gateway & fw interface etc. I'm unable to ping R1 & R2 from the Firewall.
I've spent more than 6 hours on this. 
I faced the same issue a week back , then I uninstalled vmware workstation 15 and installed 14 version, made some registry tweeks to make it compatible with windows 10. Then I just change the CD/IDE settings to Aconnection preference to "use physical device". And it worked all good. 
 
This morning I again faced this issue.  FW_ping checkdriving me nuts. I'm several times tried to do delete all vmnets, created new, installed gaia also a couple of times.
FW_ping checkdriving me nuts. I'm several times tried to do delete all vmnets, created new, installed gaia also a couple of times.
 
Don't know what is going wrong.
Last year, I created the same lab on my Windows 7 PC and never faced such silly issues.
Please have a look and let me know what you guys think the issue would be.
 
 FW_interfaces
FW_interfaces FW_route table
FW_route table
 R1 properties
R1 properties R2 properties
R2 properties VMnet configuration
VMnet configuration R1_vyatta interfaces
R1_vyatta interfaces R2_vyatta interfaces
R2_vyatta interfaces
It has also happened that at one instance FW was able to ping R2 and not R1 but after I changed the vmnet settings, then again back to ground zero.
 
PS : Gateway on R1 is eth1 i.e. 136.1.121.12
        Gateway on R2 is eth2 i.e. 136.1.122.12