Best way to handle a move to a new cart

[hologos]

We are moving to a new software and I have some Google SEO concerns.

Currently, our site has very good rankings for product-specific URLs, in the form of http://www.mysite.com/detail.asp?product_id=12345. Our new software includes an out-of-the-box detail page of the form: http://www.mysite.com/productdetails.asp?productcode=12345.

1. I now have the ability to mask URLs server side, transforming the asp URL into an SEO-friendly static looking URL (../productdetails.asp?productCode=12345 becomes ../productdetails.12345.htm) Can I expect to maintain (or to quickly achieve) the same product-specific rankings for my high ranking URLS if I change the detail page URL and all internal references to it to the more SEO-friendly type of detail page?

2. I suspect that most folks would agree that the answer to 1. is no, so my next question: What is the most SEO-friendly way to change the new detail page to resemble the old one? I can easily change the name of the page (from productdetails.asp to detail.asp), but I wonder if there is a quck-and-dirty way to change the URI string \such that the Google bot reads ../detail.asp?product_id=12345 instead of ../detail.asp?productCode=12345. Any suggestions?

[cyanide]

If you are on an Apache server, then it's a matter of writing some mod_rewrite code and put it into the htaccess file of your root directory.

I am assuming you are on a Windows machine, therefore you could be looking at a commercial app, such as
http://www.isapirewrite.com/
http://www.helicontech.com/linkfreeze/
http://www.qwerksoft.com/products/iisrewrite/

[hologos]

Thanks, cyanide. One of these windows iis solutions should do the trick.

[hologos]

An afterthought: doing it the rewrite way, do I need to worry about duplicate content penalties? That is, is there any way that Googlebot will find my rewritten URLs (http://www.mysite.com/detail.asp?product_id=12345) AND my new (actual) URLs, (http://www.mysite.com/productdetails.asp?productCode=12345)? Given that the content will be identical, a penalty is a concern here. Or, since all of the actual URLS would be rewritten before being passed on to the bot, would Google not find the actual ones?

Thanks!

[cyanide]

There's a few things to consider here.

If you are successful in getting the mod-rewrite to forward old urls to the new urls, then those old pages won't show because they are simply forwarded and SE bots will follow right along.

In addition, if you are planning to take the old cart off-line completely, there is a chance that old urls may continue to show up which will mean the appearance of a 404 page.