When Written: Dec 2008
There comes a time in many relationships when they come to an end. This article is about how to end your relationship with your ISP and move to a new and better featured ISP. As with any such parting of the ways things will go much more smoothly if you can stay on speaking terms with your old partner; if this is not possible then expect a bumpy ride. The reasons for wanting to change are many and varied from a need to use a technology that the old ISP does not support (although this rare nowadays) right through to a breakdown in confidence of the service provided.
There are four main areas that effect most companies and their internet presence; their web site, email, domain and their connectivity from the office. I thought I would go through some of the pointers to watch for when making such a change as I have often been asked how best to migrate these services and been involved in sorting out a mess caused by a consultant getting it wrong. If given a little thought then the move to a new ISP can be seamless. I am very grateful to Richard Palmer of the owner of the ISP Merula ( www.merula.net ) for his advice whilst writing this article and also for his ‘top tip’ when transferring from one ISP to another ‘check the cancellation terms with the old ISP before starting the process; some will need notice, etc and if you get it wrong you can end up paying for two at the same time’
Merula one of the more helpful ISPs out there.
Moving the hosting of your domain and its DNS records is something that needs great care and if done incorrectly can not only break everything but, as the changes to DNS can take a few days to replicate around the internet there can be a long break in services if you are not careful. To transfer a domain from one ISP to another ISP varies on the type of domain, the easiest being .co.uk domains, as with these all that is required is the transferring of the IPSTAG from your old ISP to the new one. Since transferring the IPSTAG only changes the ‘technical control’ the gaining ISP then needs to set up the DNS records as soon as possible because although the releasing ISP will hold the old records for a few days to ‘overlap’. Once the new DNS records are setup it is important to instruct the old ISP to remove the old DNS records otherwise there will be confusion caused by any differences in them. Make sure that the DNS records are all set up correctly before this occurs, otherwise everything and I mean everything will break. This is just what happened with one client. So concerned were they about moving the Web hosting to the new ISP their ‘expert’ didn’t even stop to think of the ramifications to the email which went down for a couple of days!
So what should you do? If all you are wanting to do is to move the web hosting then there are several options. A web server like any server on the internet normally is referenced by an IP address. I fact if you can’t reference your new ISP’s web server by an IP address then you should consider a different ISP. When you have all the files that make up your web site on the new server space you can ask your old ISP to make the changes to your DNS so it will then point to the new web server. Before you make the DNS change you can simply redirect traffic to your new web site, this is handy during the period where the DNS is updating over the internet or if your old ISP is reluctant to make the DNS changes for some reason. This can be done either by reconfiguring the old web server or putting a piece of code on each page of the old site with some script to redirect the request to the new site. Or you can use a meta tag to achieve this in a normal static HTML page. If you can’t re-configure things at your old ISP to redirect web traffic to the new web server then the second best way to achieve almost the same result is to remove all the files on the old web server and then put your redirect code in the ‘404’ error page. This is the error page that is served if any page is not found on the web server. By making such changes to your old web server you can be sure that should the DNS changes take a long time to propagate round the internet then visitors to your web site will arrive at the correct new site. A sample of adding redirect code to a static HTML page I have shown below:
<META HTTP-EQUIV=”REFRESH” CONTENT=”10”>
Please wait whilst we redirect you to our new web site
So with your new web site up and running on your new web server and visitors being redirected, you can now make the changes to your DNS to point the ‘WWW’ host entry to the new web server IP address. Whilst these changes should be seen within in 24 – 72 hours you need to wait at least two weeks for your DNS changes to be fully propagated around the Internet and the old values of IP addresses to be flushed from the various DNS and Proxy servers out there. For some reason AOL users seem to be one of the last to see such changes. When everything has settled down you can finally stop using your old ISP for web hosting.
Now we move to email hosting. Moving this to a different ISP can cause a few problems. The first question to ask your new ISP is whether they allow ‘Authenticated SMTP’ as this allows the sending of emails from any network or can you only sent emails if your mail server is on their network?
There are two main types of mail hosting, in one type your emails are held on the ISP’s server and you log in to collect it either through a web interface or via an email client like Outlook. The other scenario is where you run your own email server and the ISP sets the DNS to point its MX record to the external IP address of your email server. In this case all other email servers would look at the DNS for a particular domain to see which mail server handles the email for that domain by looking at the ‘MX’ record in the domain’s DNS and send the email to the mail server specified in there. Let’s assume that you are not moving your ADSL supplier at the same time, because if this was the case your external IP address would change as well, and you will have other problems. Leave that for another day; don’t try to move it at the same time otherwise it could end in tears.
Taking the scenario where you are running your own email server first: you need to tell the ISP who is going to be handling your DNS where to point the MX record of your domain and you also need to be sure that the external SMTP address on your email server is pointing to the correct ISP’s mail server. Bear in mind is that a lot of ISP’s will not allow you to send emails through their SMTP servers if you are not part of their network, so if your ADSL is supplied by one ISP you need to use this ISP’s SMTP server address for your outgoing emails, either in your email client program if they are holding your emails, or in the configuration of your own email server.
With the other scenario, where the ISP holds your email on their mail servers and you collect it, then when you point your DNS at the new ISP it will mean that your email will start to go to your new ISP’s email server. Before you move to the new mail service you just need to do a final login to the old ISP and download any email not gathered from it. ISP’s usually run POP mail servers and this means that when you login to get your email, once it has downloaded to your client or your email server it is then deleted from their mail server so be aware of this and plan your steps accordingly. Once you are sure you have got all your emails that you want, you can stop the email service on your old ISP, and then enable the DNS changes on the new ISP. Any email arriving whilst this change-over takes place should not be able to find a mail server and then ‘bounce’ and be automatically resubmitted usually for up-to five days. Again it is very handy to have the full co-operation of your old ISP during this process.
If your email client settings use the full names of the servers and not IP addresses then assuming the new DNS has entries for these names then you should not have to change anything in the client.
As you can see there are plenty of places where you can trip up with such a move. It is not difficult to achieve in a seamless fashion but it needs a full understanding of the existing setup and a bit of planning, the co-operation of all parties involved helps as well. Don’t forget any add-on services that also might be affected like spam filtering services that might also need changing their configuring. If after reading this you are not happy about doing this or do not understand the mechanics of DNS and IP addresses then don’t even attempt this on a domain that is critical to yours or anyone else’s business. Get in someone who does understand it, but check that they understand the current setup before they start changing things, not like certain ‘consultants’ I could mention!
Article by: Mark Newton
Published in: Mark Newton