In this post this post I talked about how I use an external DNS supplier as part of my web hosting provision. One of the major advantages that this provides is the ability to do near-instantaneous switching between hosts. This avoids the usual 24-48 hour lag that is associated with nameserver changes and minimises the period of doubt during which you cannot be sure whether email for the domain will be delivered to the old host or the new.
To do this I use the template function in my DNS control panel to create templates for the old and the new hosts. Then I set up the domain with the old host values for the DNS records and set the TTL value on the to 180 (3 minutes). Then I switch the nameservers from the old host to the DNS supplier. At this point nothing has changed.
Once the nameserver change has propagated then I switch the domain from the old template to the new. Because of the low TTL value the DNS servers around the net should not cache the old values from more than three minutes, so that is all it takes for the switch to be universal. The beauty of this process is that if there is a problem with the new hosting then it is just as quick to switch back. Finally once you are sure everything is as it should be then you can set the TTL values back to a normal setting (say 24 hours).
The information is provided 'as is'. It has worked for us,
but it may not work for you, so you use it at your own risk. We can't
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Geographical coverage: AlphaOne Computing Services
provides a range of small business computer support and I.T. services throughout Sussex, including
Brighton, Hove, Shoreham, Worthing, Steyning, Burgess Hill,
Haywards Heath, Crawley, Lewes, Newhaven, Seaford, Uckfield and Eastbourne.
