Client Side DNS Caching Is A Pain

Imagine this, your client has been waiting for a few months for that brand new website to replace to old one. Deployemnt time comes, you have done everything, according to the check-list:
File migration – done
Database sync – done
Configuration files – done
Name server – checked, all correct.

All done and you can see the new site running. But somehow some of your clients are still seeing the old site? Why?

Well, chances are the client’s computer would have a local cached version of the DNS. Depending on the system, it might take up to 24 hours for it to be refreshed. But in one case it did not do that for at least 48 hours. How do you resolve this issue where there might be hundreds or thousands other computers are still looking at the old site?

Well, it would not be an issue if there is no hosting server change, but if there is there might be some other things which we can do to prevent this from happening.

Should we :
Transfer the old site onto a new hosting first and then install the new site after? This might not be possible if we do not have the access to the file structure of the old site.

In another case, which baffled my for hours, was that the client was still seeing the old site on a laptop, even just about everyone in the world is seeing the new one. Initially I thought it was the case where the DNS had not been fully propogated yet, but this was not the case. It turned out that in the hosts (Window file) had an entry specifically for the domain name which I was working on, masking the IP address so that it was pointing to the old server! Who would have thought that?

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