Hi kanniganti,

> connections on IPV6 and if IPV6 is not available it has to connect to IPV4 seamless by the application

In general, this seems to be a purely client-side issue: The client will at some point check for DNS names - asking i.e. for an "A" record (and will receive an IPv4 address with the reply) or an "AAAA" record (and receive an IPv6 address). So you'd have to configure your client to ask for the IPv6 address first. If it supports connecting to multiple servers, you could provide different DNS server names in the right order to your application. Or if the application is dual-stack enabled, maybe it does have an option to first query the AAAA record (with the same name as the A record)? If the client retrieves the server information via SRV records, you ought to be able to just set correct priorities with two or more SRV records, some pointing to the IPv4 DNS name and others pointing to the IPv6 DNS name.

Generally, it boils down to "what does your client offer, how will it determine the server to connect to?"

Regards,
J