# pseudo code!  Not perl!
# 
# example.com = 192.168.0.10 
# www.example.com = CNAME example.com
# lungfish.example.com = 192.168.0.10 
# fruitbat.example.com = 192.168.0.12

compare_host_names('example.com','example.com) == true
compare_host_names('example.com','www.example.com) == true
compare_host_names('example.com','lungfish.example.com) == true
compare_host_names('example.com','fruitbat.example.com') == false