Posted by leepeng on July 3, 2009
When new clients approach us for website revamp and indicate that they want to keep the existing hosting, the first thing we normally like to check with them is the server the website is running. We develops websites in PHP5 and ASP.NET 2 so this information is quite useful for us.
However the most answer is “I don’t know”.
So we need to find a way check this information.
Firefox has a cool add-ons call HTTP Header which helps us in this area.
There is a small bug in the current version which showed Japanese.
You will notice that this add-on can help you to know the web server type (apache / IIS) and the application server (PHP 5, ASP.NET 2).
These information are actually embeded in the HTTP header and our browser does not show them. This ad-on do no magic but to show whatever existing information to us.
Anyway, if you are not Firefox user, start using Firefox now. You will be happy always 
Posted by leepeng on
Have you ever encounter the situation which after getting your hosting for a while, you start to notice the email send from your server couldn’t reach your recipient; especially when the email is sent direct from the webserver using sendmail (e.g. mail function of PHP)
I myself is not hosting expert. However, after a few shocks, I somehow figure out some simple mis-configuration that easily happen to hosting engineers while setting up new server.
Two main cause: 1st is the missing of qualified domain name and second is missing of SPF setting.
These two can be observe easily by looking at the email header content in GMail. Try create a simple testmail.php which will send email to your GMail account using PHP’s mail function.
<?php
mail("leepeng@gmail.com", "Test Mail", "Test 123", "From: something@xx.com");
?>
Then open the source / original message of the email.
Here is an example of “Healthy” email
Delivered-To: leepeng79.chen@gmail.com
Received: by 10.142.43.3 with SMTP id q3cs50083wfq;
Tue, 30 Jun 2009 02:03:53 -0700 (PDT)
Received: by 10.114.255.12 with SMTP id c12mr12997276wai.11.1246352633584;
Tue, 30 Jun 2009 02:03:53 -0700 (PDT)
Return-Path: <bounce@organisedmum.com.sg>
Received: from organisedmum.com.sg (organisedmum.com.sg [116.12.50.227])
by mx.google.com with ESMTP id 1si12092283pxi.65.2009.06.30.02.03.52;
Tue, 30 Jun 2009 02:03:52 -0700 (PDT)
Received-SPF: pass (google.com: best guess record for domain of bounce@organisedmum.com.sg designates 116.12.50.227 as permitted sender) client-ip=116.12.50.227;
Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of bounce@organisedmum.com.sg designates 116.12.50.227 as permitted sender) smtp.mail=bounce@organisedmum.com.sg
Received: (qmail 20407 invoked by uid 48); 30 Jun 2009 17:03:51 +0800
Date: 30 Jun 2009 17:03:51 +0800
Message-ID: <20090630090351.20397.qmail@organisedmum.com.sg>
To: leepeng79.chen@gmail.com
Here is an example of “unhealthy” email
Delivered-To: leepeng79.chen@gmail.com
Received: by 10.142.43.3 with SMTP id q3cs126200wfq;
Thu, 2 Jul 2009 00:18:36 -0700 (PDT)
Received: by 10.224.28.130 with SMTP id m2mr10174634qac.52.1246519115111;
Thu, 02 Jul 2009 00:18:35 -0700 (PDT)
Return-Path: <nobody@vm4.kfc>
Received: from vm4.kfc (202-150-217-11.rev.ne.com.sg [202.150.217.11])
by mx.google.com with ESMTP id 15si3872346yxe.130.2009.07.02.00.18.34;
Thu, 02 Jul 2009 00:18:34 -0700 (PDT)
Received-SPF: neutral (google.com: 202.150.217.11 is neither permitted nor denied by best guess record for domain of nobody@vm4.kfc) client-ip=202.150.217.11;
Authentication-Results: mx.google.com; spf=neutral (google.com: 202.150.217.11 is neither permitted nor denied by best guess record for domain of nobody@vm4.kfc) smtp.mail=nobody@vm4.kfc
Received: from nobody by vm4.kfc with local (Exim 4.69)
(envelope-from <nobody@vm4.kfc>)
id 1MMGZG-0005GT-VS
for leepeng79.chen@gmail.com; Thu, 02 Jul 2009 15:18:51 +0800
To: leepeng79.chen@gmail.com
If you observe, you will notice that the “healthy” example has a qualified domain name which associate with the IP address. However the “unhealthy” exmple does not have a qualified domain name. The mis-configure one will either has setting localhost or just the server name in the private network (vm4.kfc for this example)
Second is the “healthy” example can pass GMail’s SPF check but the “unhealthy” one have the mark of neutral. SPF is to help make sure the server is not used for spamming. When GMail said it is neutral, it means GMail don’t know if the server is right or wrong.
My experience is that GMail has been very generous in their antispam as it will accept most of the emails. However, if you notice these 2 mis-configuration, it will be likely the mail would not able to deliver to Hotmail, Yahoo, AOL or some corporate email addresses.
So now you have something to argue with the hosting engineer 
The last thing to check is to make sure your server’s IP address is not blacklisted. One common place to check is at www.spamhaus.org
Posted by John on July 2, 2009
