You can configure the DNS server on Windows to make use of a specific address.
Read:
http://support.microsoft.com/kb/813964/#XSLTH4147121123120121120120
Why are you running DNS in a cluster? Just a thought because you would be better served running TWO DNS servers simultaneously.
With regards to webservices, Ive seen this when you setup SSL on a webservice and havent specifically allocated the SSL ip address (it defaults to the machines default IP) Have a look under the advanced settings in IIS at the IP used for SSL.
My 2c
My views are my own and in no way reflect those of my employer.