Thanks for the response. I am not very good at DNS except knowing the basic components of basic component of Zones and records etc.
Whatever i read for DNS validation you need to manually create TXT Record for domain validation. I also read and you also mentioned about Creating/Removing the _acme-challenge TXT records although not sure how it is done automatically. If you can throw some light on that or point to a doc where it is mentioned in detailed?
I also came across to the below thread, and it seems this person has done same requirement and using the same Cisco Product as me and used CNAME to make it work.
I appreciate all your responses. +5
Thanks & Regards,
Alok