Name Resolution

When i resolve an ip address to a hostname, it is different form when i resolve the host name. e.g

I type ping – 20.63.37.57, it returns lll.co.uk but when i ping ping -a lll.co.uk, it returns a different ip address such as 20.63.37.21.

We have DHCP and DNS servers and i have flushed the DNS cache on the PC. What else can i do to resolve this problem?

Thanks