I Learned Something About IP Caching Today That You Might Find Interesting

This is something that I had never run into before and I am passing it along
since some of you may have sites (such as membership sites) that your
customers access on a regular basis.

Now, I am not a tech person so I can't really explain this in really good
technical terms (which may be just as well for you non techies) so I am
going to explain it in simple English.

Let's say John Doe accesses your site and has it bookmarked and their ISP
also has the IP address cached. This way, when you go to the site, you'll
notice that it comes up right away.

Well, if for some reason, your hosting company makes some updates and
in the process, changes the IP address of the site, your customer's PC, when
they go to access the site again, will NOT find it, even though it is still up.

Now, according to my tech guy, eventually this gets flushed out and
when the customer goes back to the site, maybe a day later or whenever,
the site WILL come up. But until the IP or DNS gets flushed, it won't.

This just happened to me. I could get to my sites from one PC (hadn't been
on it before the update) but couldn't get to the sites from the PC that had
just accessed it before the update.

If you have a very active site, this could cause a customer service
nightmare during that period before the DNS gets flushed.

You can manually flush your DNS by pulling up a DOS prompt and typing in

ipconfig/flushdns

However, your customers and/or members won't know to do this.

It took me forever to figure this out, which was later confirmed by my
tech guy at the hosting company.

I don't know how often something like this will happen. It is the first time
this has happened to me since I've been online, but in case you ever find
that you can get to one of your sites from one computer but not from
another, this is probably why.