The search engine friendly way to merge domains

In common with many website owners, I have multiple domain names pointing at a single website (, and There’s nothing wrong with that (it’s often used to present localised content or to protect a trademark) but certain search engines will penalise sites where it appears that multiple URLs are being used to present duplicate content (hence increasing the link count and inflating the position within the index).

The trick is to ensure that the domains are merged in a manner which is acceptable to the major search engines. It’s generally accepted that the way to do this is to choose the primary domain name (in my case, that’s and to rewrite any requests received by the web server(s) on any secondary domain names so that they are redirected to the primary domain name (using HTTP status code 301 – moved permanently).

For a site running on an Apache web server with the mod_rewrite module compiled, this is achieved using some directives in the .htaccess file. A description of the required code can be found in various locations, including Brian V Bonini’s 301 permanent redirect article but my site uses some code from a recent .net magazine article to combine the domain name rewrite with the placement of any missing www prefix:

Options +FollowSymLinks
RewriteEngine On
RewriteCond %{HTTP_HOST} ^primarydomain\.com$ [NC,OR]
RewriteCond %{HTTP_HOST} ^(www\.)?secondarydomain\.com$ [NC]
RewriteRule ^(.*)$$1 [R=301,L]

After making the changes, it’s important to check the server headers (e.g. using the SEO Consultants check server headers tool) and ensure that the server is correctly returning an HTTP status code 301 that redirects to the primary domain name, hopefully resulting in an eventual HTTP status code 200 – OK:

#1 Server Response:
HTTP Status Code: HTTP/1.1 301 Moved Permanently
Date: Tue, 27 Feb 2007 15:19:42 GMT
Server: serverdetails
Connection: close
Content-Type: text/html; charset=iso-8859-1
Redirect Target:

#2 Server Response:
HTTP Status Code: HTTP/1.1 200 OK
Date: Tue, 27 Feb 2007 15:19:44 GMT
Server: serverdetails
Connection: close
Content-Type: text/html

Oops! Dropped off the ‘net for a while…

No sooner had I blogged about the smooth transfer of my domain name to a new registration agent when my website dropped off the ‘net for a day or so. I had naively thought that, if I left the domain using the old name servers for a while, everything would work as it had done previously until I was ready to launch the new site – I hadn’t reckoned on my old hosting provider removing their DNS entries for the domain, leaving all my visitors with HTTP status code 404 – not found.

As soon as I noticed, I uploaded the old site to my new server and updated the name server records for the domain but, for the time it took to propagate that update, was effectively offline.

Sorry. My mistake.

Sender verify failed with incorrect reverse DNS record

What a week! Switching hosting providers, setting up a new content management system for this blog (more on that as soon as it’s ready) and all at the same time as suffering e-mail problems as, since the middle of the week, every e-mail that I’ve sent to a particular contact has bounced back with the following message:

This is an automatically generated Delivery Status Notification.

Delivery to the following recipients failed.

Reporting-MTA: dns;

Final-Recipient: rfc822;
Action: failed
Status: 5.5.0
Diagnostic-Code: smtp;550-Verification failed for <>
550-No Such User Here
550 Sender verify failed

I have various anti-spam measures on my mail server, but this appeared to be a problem when sending mail to a particular external host – e-mail sent to the same contact via a different mail server was received with no problems.

I set about researching the 550 Sender verify failed message and found various suggestions as to what might cause such an error – the most useful of which was a message on a newsgroup post which suggested it may be caused by an incorrect reverse DNS (PTR) record (thanks to Ben Winzenz for replying to that group a couple of years ago).

Even though much of my mail was being delivered successfully, that seemed like a perfectly reasonable explanation – the reverse lookup for my IP address would have returned a hostname in the format, rather than (as confirmed by a DNS report on my domain, which also commented that “RFC1912 2.1 says you should have a reverse DNS for all your mail servers. It is strongly urged that you have them, as many mailservers will not accept mail from mailservers with no reverse DNS entry”), so I set about getting the record updated by my ISP (it has to be done by the owner of the IP address block).

Initially I asked my ISP to add my mail server’s DNS name as a second PTR record for my IP address but in practice I found that DNS responded in a round robin pattern (rather than returning all the matching records) so I couldn’t rely on a consistent response and was still experiencing mail delivery failures. Finally, after reverting to a single PTR record for my IP address and waiting for DNS propagation (again), I was able to successfully send e-mail to the contact with whom I’d previously experienced issues (phew!).

As more and more hosts take action to prevent unsolicited commercial e-mail (UCE – also known as spam), this is likely to be a more common occurrence and it just underlines how important a correct DNS configuration is.

Simple UK domain name transfers

I’ve been the legal registrant of the domain for almost 8 years now and it’s the domain name that drives most of the traffic to this website. Consequently, I would be very upset if I was to lose it and I’ve never been confident enough to move it away from the ISP whom I first registered the domain through (PlusNet/Force 9). Even though I have an ADSL line on a separate account, I have kept a dial-up account open with them for many years, just to maintain the webspace and domain name. In recent months, however, I’ve been getting close to the bandwidth limit on that service and they have been pretty poor at responding to my queries about what will happen once my traffic gets too much (I even offered to pay more money). Support from PlusNet/Force 9 has always been variable (excellent or poor – nothing in between) so I decided that it’s time to move on and my friends at ascomi are able to provide me with a very reasonably-priced hosting service with plenty of headroom.

So, it was with some trepidation that, this afternoon, I finally changed the IPS tag from FORCE9 to FASTHOSTS and transferred the domain name to my account at UKReg. That was it. Easy. Once the transfer had taken place, I could update the DNS server details to point anywhere I like (although at the moment they are still pointing exactly where they always have been, just until I get the new website up and running on my server at ascomi).

I was amazed at how efficient the process was – so much so that I raised a paranoid support call with UKreg, just to make sure that they will re-register my domain when it comes up for renewal.

I appreciate that for many people this is a very simple process and why does it justify a blog post? Well, it was a very big deal for me and I’ve been putting it off for years (literally). I just wanted to be sure that anyone who has similar issues and who stumbles across my ramblings can have their concerns laid to rest.

Further information on UK domain name transfers can be found at Nominet.

Do we really need trusted computing and digital rights management?

I’ve never thought much about the trusted platform module (TPM) inside my PC but recently I’ve heard a lot about the rights and wrongs of digital rights management (DRM) – a technology which looks certain to make ever greater use of the TPM.

I also came across a (well-produced) short video about trusted computing. It makes a very interesting point based on a definition of trust (confidence) being a “personal believe [sic] in the correctness of something… a deep conviction of truth… which cannot be enforced… [and which] always depends on mutuality”.

In the last few weeks, I’ve heard a lot about Microsoft getting bad press for implementing DRM technologies in Windows Vista (it seems to me that Hollywood gave them very little choice in order to allow Vista to play back high definition content); Apple’s Steve Jobs has spoken out in favour of dropping DRM in iTunes (and Daring Fireball published an alternative view on what Jobs might actually be saying – my view is that it’s an elaborate ploy by Apple not to appear as “the bad guys” as unrest with the questionable legality of the iTunes Store grows in mainland Europe); and EMI are reported as considering the release of their catalogue in a DRM-free format (make the most of it before they are bought by Warner).

Of course, supporters of DRM (which may be enforced via TPM) insist that without it, piracy and theft of copyrighted content will spiral out of control. Perhaps they should look at why this might be – only last week I wrote about how I had considered downloading music from underground sources because I couldn’t get hold of it legally. Over-zealous use of DRM will drive law-abiding citizens like myself to break copyright because the latest wave of DRM measures goes too far. With previous content (including digitally-produced CDs), I could make a copy for personal use under fair use legislation. So why should I have to buy high definition content over and over, just so that I can watch it on my TV, my computer and my iPod?

As the transition of audio/video content to an online delivery mechanism continues to gather pace, the vast majority of consumers will still buy their music/video legally – at least in the first world – and let’s face it, do we really need to clamp down on this phenomenon in the developing world? Isn’t that just greed?

Sony BMG’s rootkit fiasco showed how copy protection could be taken too far – a complete breakdown in the public’s ability to trust of one of the world’s largest content providers. If I’m to trust the content providers not to put bad things on my computer and if trust really is, by definition, mutual then why do we need DRM?

(A few moments ago, a poll of almost 6000 readers of the UK Financial Times – not exactly known for dumbing down to the masses – showed that 98% of those polled were in favour of music companies dropping DRM).

Virtual PC is alive and well

I’ve commented before that I wasn’t sure what the future held for Microsoft Virtual PC as much of the marketing and visible product development for the last couple of years has related to Virtual Server. Well, despite killing off Virtual PC for Mac, the Windows version appears to be alive and well as Virtual PC 2007 has been released.

I haven’t had time to check it out yet (I’m using Virtual Server 2005 R2 at home and until recently was using various VMware products at work) but I’m sure more details will become available in time at John Howard‘s blog.

Bye bye Blogger?

Recently, I’ve written a couple of posts which hinted at the problems I’ve been having since I was involuntarily upgraded to Blogger‘s new platform and tonight was the final straw. For a while now, I’ve wanted to implement a category system for posts and a couple of months back I did actually start to tag my posts at in preparation for following Peter Chen’s advice for creating Blogger categories.

Unfortunately, the delicious2Blogger (D2B) method does not work with the new Blogger and to implement Blogger’s label system (in order to put a tag cloud on the site using phydeaux3’s label cloud code) I’ll need to upgrade my “classic template” to a “layout”. The problem is, that layouts are not supported for externally hosted sites that are published using FTP (like mine), so I’ll be stuck with my existing template, which has been broken since the upgrade.

Seeing as Blogger seems to be so full of limitations and I’m in the middle of a site redesign anyway, I’m seriously considering a move to a WordPress-based site – as long as I can preserve all the links and comments. I’ve also been having some issues with my hosting provider (and the fact that they have recently been bought by BT doesn’t fill me with joy either) so I’m probably going to move away from them too.

I’ll be trying to minimise the impact on blog readers and hope to maintain the domain name and all the links, but please bear with me if there are a couple of hiccups along the way.

Text me outta here

When I was about 15, I remember using a telephone engineering number to get the phone to ring, then pretending that it was my friend’s Dad on the phone, that we were in trouble, and that we had to go to his house right away – just to get my girlfriend to leave so I could hang out with my mates!

Fast forward 20 or so years and teenage girlfriends are definitely a thing of the past (I’m happily married, with two lovely kids). The engineering code that I used to know is also long since confined to a distant memory (but you can do something similar in the UK with 17070); however there is a new service for those who need to escape from dodgy dates, or other potentially sticky situations. For £1, text me outta here will send an SMS message at a pre-defined time and you can either ignore it (if things are going well) or use the excuse you dreamed up previously to get you out of a situation. It’s only been running for a few weeks but sounds like an interesting service to me!

Portable applications – an alternative approach to mobile computing

I’ve been playing around with the idea of running operating systems from USB flash drives for a while now but the main problem is USB boot support in the hardware I use (most notably the Fujitsu Siemens Lifebook S7010D that I use for work doesn’t support it).

A while back I wrote about my experiences of booting Windows PE from a USB flash drive (and I believe that new versions of PE make this easier) but the reality is that I haven’t needed this – it not really anything more than a challenge that I set myself to see if it could be done and for those (up to now, theoretical) “system down” occasions there are CD-based solutions that I can use (e.g. Knoppix STD, Trinity Rescue Kit or Winternals Administrators Pak).

For other occasions (like working on someone else’s PC), there is the option of a portable application. I tried out two such packages tonight (my favourite Windows FTP program – FileZilla – and Mozilla Firefox) and was very impressed. Neither of these applications is installed on my wife’s Windows XP PC and yet I was able to run the portable versions of the them both from my USB flash drive without leaving any files behind. It’s the ultimate in mobile computing – literally anytime, anyplace, anywhere – as long as you can borrow a (Windows) PC!

There are alternative solutions such as U3 and MojoPac but, as far as I can tell, these rely on kernel hacks to implement technology such as roaming desktops and the beauty of the Portable Applications solution is that, even though there is an application “suite” available, I can just run the individual applications that I need, on any Windows PC, without any specialist hardware – and it’s free.

Don’t be misled by the Windows Vista myths

In recent months, there has been a lot of criticism of Microsoft Windows Vista in the press and elsewhere – I know because I wrote some of it; however it’s good to see Deb Shinder’s TechRepublic article entitled don’t be misled by these 10 Windows Vista myths, which seems to be a thoughtful and well-reasoned view of why a lot of the hype (both from Microsoft and from the anti-Microsoft camp) needs to be taken with a pinch of salt.

Unfortunately, many of the comments posted about the article are ill-informed, or even just plain old trolling. Somewhat ironically, I came across the article via MacBreak Weekly (episode 28) – a podcast which often displays Apple fanboy tendencies.