c# dns lookup from code?

Is there a way to do a DNS Lookup to get the DNS name given an ipaddress pragmatically, using the default dns server configured on the IIS server?

I don't want to enable server level DNS lookup at this time. I think this would consume unnecessary time and resources since, I have to do the reverse dns for only a few ip's based on some condition in the c# code.

Windows Server 2003 IIS 6
.NET 2.0
C#
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