`emailrelay-check-ipaddress.js <emailrelay-check-ipaddress.js>`_
----------------------------------------------------------------

.. code:: javascript

    //
    // SPDX-FileCopyrightText: 2026 Graeme Walker <graeme_walker@users.sourceforge.net>
    // SPDX-License-Identifier: FSFAP
    // 
    // Copyright (c) 2026 Graeme Walker <graeme_walker@users.sourceforge.net>
    // 
    // Copying and distribution of this file, with or without modification,
    // are permitted in any medium without royalty provided the copyright
    // notice and this notice are preserved.  This file is offered as-is,
    // without any warranty.
    // ===
    //
    // emailrelay-check-ipaddress.js
    //
    // An example E-MailRelay filter script for Windows that
    // verifies the submitting client's IP address. The IP
    // address is read from the envelope file. Invalid IP
    // addresses are rejected by deleting the two message
    // files and exiting with the special exit code of 100.
    // Note that this checks the IP address very late in the
    // submission process; a firewall or DNSBL check might
    // work better.
    //
    try
    {
    	var content = WScript.Arguments(0) ;
    	var envelope = WScript.Arguments(1) ;
    	var fs = WScript.CreateObject( "Scripting.FileSystemObject" ) ;
    	var ts = fs.OpenTextFile( envelope , 1 , false ) ;
    	var txt = ts.ReadAll() ;
    	ts.Close() ;
    	var re = new RegExp( "X-MailRelay-Client: (\\S*)" , "m" ) ;
    	var ip = txt.match(re)[1] ;
    	var ok = ip === "1.1.1.1" ; /// edit here
    	if( ok )
    	{
    		WScript.Quit( 0 ) ;
    	}
    	else
    	{
    		WScript.StdOut.WriteLine( "<<not allowed>>" ) ;
    		fs.DeleteFile( envelope ) ;
    		fs.DeleteFile( content ) ;
    		WScript.Quit( 100 ) ;
    	}
    }
    catch( e )
    {
    	// report errors using the special <<...>> markers
    	WScript.StdOut.WriteLine( "<<error>>" ) ;
    	WScript.StdOut.WriteLine( "<<" + e + ">>" ) ;
    	WScript.Quit( 1 ) ;
    }
    

.. _../examples/emailrelay-check-ipaddress.js: emailrelay-check-ipaddress_js.html