Hi
I am looking to have an NTP server that will support both ipv4 and ipv6 clients. Is there anything specific about the configuration that I should be looking at?
A fine grained clock on the host hardware and os support. A low latency nic. Usually, such a function does not monopolize a host.
Thanks DGPickett, I jave an external clock source and I have used the ntp.server as my template for ntp.conf,
normally I would just use
server <ipv4-ipaddress> prefer
I am assuming that I still need this for the ipv4 clients
but can the ipv6 clients resolve this or do I need to have a separate ipv6 address mapped
Well, that is just ipv6 integration, not NTP. Who does your router(s)?
I have not gone that far into the lan room! 
If the local router and hosts on your collision domain do what you do, then it should not be a problem. I seem to recall all IPv4 addresses have an implicit equivalent ipv6 address. Most IP stacks are IPv6 compatible now. Your server should arp for both. NTP usually runs on the payload of the IP UDP packet, and should not much care if grandma is ipv4 or ipv6. The people 2 floors up take care of that. I have not seen any ipv6 used to configure anything, yet, as the local world seems happy to be ipv4 to the casual viewer, or more generally name driven, and we have NAT and intranet 10. and the like behind NAT firewalls, stretching the ipv4 space. Why pay for lots of real IP addresses for the intranet, when there are 16 million for free!
What version of NTP are you using? On what system? v4.x or later can support IPv6.
Hi I am using ntp v3, some clients will be inside the firewall some outside, some will be ipv6 and some will be ipv4, if I am using an ipv4 address in my ntp.conf is ntp clever enough to resolve it
IPv6 support was added in NTP v4. You would have to check Solaris documentation to see if Sun/Oracle added support for IPv6 to their version of NTP v3. They may have!
This blog might be of interest to you: Solaris IPv6 Packages
Still, I think if you can ping it, ntp could hit it with udp packets!