Welcome to the Q&A Forum
Browse the forum for helpful insights and fresh discussions about all things SEO.
After more than 13 years, and tens of thousands of questions, Moz Q&A closed on 12th December 2024. Whilst we’re not completely removing the content - many posts will still be possible to view - we have locked both new posts and new replies. More details here.
If its possible to fix the site without altering the directory and URL structure, that's going to be your best option.
However, I'm guessing you're going to be fixing URLs as well, and if that's the case you'll want to use 301 redirects to tell search engines where the content has gone. See http://www.tamingthebeast.net/articles3/spiders-301-redirect.htm
Finally, wherever possible try to get the owners of the sites with backlinks to update their links to you.
Yeah check out URL Normalization under the Indexing tab.
Rel Canonical should help with the issue. You should also go into google webmaster tools and put in all your URL parameters, so the crawler has a better idea of whats going on with being able to get to a particular resource with several URL variations.