It’s a simple thing, but quite useful. In the organization where I work we have over ten web servers, so oftentimes the location of a problem can be difficult to pinpoint. In this line of thought I was asked to create a ColdFusion page which tries to communicate with our SMTP server, and spit out 200 OK if it is available. So here’s one approach.

<cfsetting showdebugoutput="false">

<cfscript>
	success = 0;

	try {
		socket = createObject("java", "java.net.Socket").init(
			javacast("string", "mailserver.address.com"),
			25
		);
		socket.close();

		success = 1;
	} catch(Any ex) {
		success = 0;
	}
</cfscript>

<cfif success>
	<cfset getPageContext().getOut().clearBuffer() />200 OK<cfabort />
<cfelse>
	<cfset getPageContext().getOut().clearBuffer() />404 Not Found<cfabort />
</cfif>

This code simple attempts to establish a socket connection to the mail server on port 25, and if successful, spits out 200 OK, otherwise it reports 404 Not Found. On failure the java.net.Socket class throws an exception.