pf » DNS Query with ColdFusion

It has been a while since I've posted one of these java + cfml tricks, so here's a neat one for ya'.

You can use the Java Naming and Directory Interface (JNDI) to perform a DNS query in ColdFusion.

In the example below I use JNDI to look up the MX records (mail exchangers) for gmail.com:

<cfset env = CreateObject("java", "java.util.Hashtable")>
<cfset env.put("java.naming.factory.initial", "com.sun.jndi.dns.DnsContextFactory")>
<cfset env.put("java.naming.provider.url", "dns://10.0.0.65")>
<cfset env.put("com.sun.jndi.dns.timeout.initial", "2000")>
<cfset env.put("com.sun.jndi.dns.timeout.retries", "3")>
<cfset dirContext = CreateObject("java", "javax.naming.directory.InitialDirContext")>
<cfset dirContext.init(env)>
<cfset type = ArrayNew(1)>
<cfset type[1] = "MX">
<cfset attributes = dirContext.getAttributes("gmail.com", type)>
<cfset atribEnum = attributes.getAll()>
<cfloop condition="#atribEnum.hasMore()#">
<cfset attribute = atribEnum.next()>
<cfoutput>#attribute.toString()#</cfoutput><br />
</cfloop>

You will want to point the java.naming.provider.url to the IP address of a dns server, in my case I use: dns://10.0.0.65.

You can also make different types of queries such as A (address) or TXT (text records).

I have written a commercial DNS component for ColdFusion as well.