This VB function returns the DNS domain name (westcoast.mycorp.com) from the passed LDAP distinguishedName (CN=Administrator,DN=Users,DC=westcoast,DC=mycorp,DC=com).

Function DN2DomainName(ByVal strDN As String)    On Error Resume Next    Dim strDomainName As String    Dim strDNParts() As String    Dim intI As Integer        strDomainName = ""    strDNParts = Split(strDN, ",")    ReDim Preserve strDNParts(UBound(strDNParts))        ' Work backwords through DN to assemble domain name    For intI = UBound(strDNParts) To 0 Step -1        If (InStr(UCase(strDNParts(intI)), "DC=")) Then            strDomainName = "." & Replace(strDNParts(intI), "DC=", "") & strDomainName        Else            Exit For ' Short circuit when we run out of "DC=" parts        End If    Next        ' Chop off leading '.'    strDomainName = Right$(strDomainName, Len(strDomainName) - 1)        DN2DomainName = strDomainNameEnd Function

Editor’s Note: This code does not check to make sure the strDomainName variable has a leading period before chopping it off, nor does it check whether the final result actually fits the form of a DNS domain name, but it will work if given proper data.