How to instruct browsers to clear any pages from our site from cache?

Question

Our old website on our old host did this... When you load www.example.com it quickly redirects you to www.example.com/main.

We actually just setup a hosted shopping cart website. We updated our registrar's DNS to point to the new hosts ns1, ns2, and ns3. We configured the software on the hosted website to handle www.example.com.

However when people go to www.mysite.com it doesn't go to the new site.

I still see the first page load from the old site, and then it quickly redirects www.example.com/main. In our new site we don't have a /main. So I see 404 not found.

Is there somewhere that I can instruct the browser to not use the cached pages?

The reason why I know this is the culprit is that all was solved when I cleared my browser's cache. However, our customers won't know to do this or would I want them to do this.

UPDATE I worked with the ecommerce hosting site and they did this...and it worked...

• They added a CNAME record that said www.mydomain.com "is and alias of" mydomain.com
• Updated SEO settings in the engine to: "redirect www to no www"

Answer 1

We often tell our clients that a DNS change can take up to 3 days, but that it often doesn't take that long.

You have made changes to your hoster, this has to be updated to their "Nameserver" until it reaches all involved parties. You have a TTL, Time To Live, you can see this as your case. Say your TTL is 8 hours, and someone did a request, they return that result until 8 hours have passed, then they'll check again with your nameserver. Sometimes you're lucky and you get new visitors or the 8 hours have just passed, other times they've just checked and you're gonna have to wait.

Tip for the next time: Set your TTL to 1 hour before you switch. This way you tell everyone "Hey, check again in one hour", which means it takes one hour at most for everyone to switch.

At this point, there is little you can do, because every setting you set, will not be viewed until the current cache has expired. If you're talking about a few users, you can try to get them to flush their DNS locally, that often might to the trick.
You might want to add a /main to your new website so you can at least catch the visitors and do something with them ("Welcome to our new site, sorry this page doesn't exists, maybe you want abc).

*There are some nuances to this, but this is the basic explanation

Answer 2

Your best option is probably to set a 301 redirect from www.example.com/main to www.example.com on the new server. It'll take some time for DNS to propagate, but once it does the 301 will be what you want.

This will tell browsers to send users to the new/correct homepage and alleviate the 404 issue for them. It also informs search engines of the new homepage so that they will reflect the correct URL too. Best for users & SEO!