Same Page, Multiple URLS- Canonical tag? Redirect?

[Telikin]

I just read this article about how google views multiple versions of the same page as different pages of duplicate content.

My website, www.telikin.com currently has many versions of the home page.  There is:

www.telikin.com
www.telikin.com/index
www.telikin.com/index.php
www.telikin.com/index.php/

All of these seem to be their own URLS,   If i use the open site explorer tool to search for links pointing to these URLS, the www.telikin.com domain shows about 700 links, and the www.telikin.com/index.php shows about 63 links.

My questions:

Is my SEO suffering as a result of having these different pages?  Does google realize that links pointing to www.telikin.com/index.php should count towards the seo of the www.telikin.com page?

If this is hurting my company's website, how do I solve this problem?  I am not versed as a webmaster, so I don't understand what the best course of action would be.  Should I request that our webmaster somehow redirects all traffic from the other URLS to the main www.telikin.com URL?

Should I be using canonical tags on all important pages?  If i do, for example, use a canonical tag on the www.telikin.com page, will Google then know to send all link juice from the www.telikin.com/index.php page to the www.telikin.com page?

We also have a Joomla blog that seems to duplicate pages many times over, but that is a problem that I will have to address another time.

Any comments/suggestions are more than welcome.

Thanks,

Dave

[Telikin]

Thank you John,

It looks like you fielded this question in the past, about 14 months ago!

http://www.seomoz.org/q/redirecting-duplicate-asp-pages

and here is a similar inquiry.

http://www.seomoz.org/q/duplicate-content-error

Its strange to me that even though you say google considers www.telikin.com/index.php and www.telikin.com/index.php/ to be the same, they produce a different result when entered into a browser.  In fact, the .php/ link ends up hiding some of the images and just showing their alt text...very strange.

I will move forward with having the web master do 301 redirects.  Thanks for the help.

[john4math]

You indeed have a duplicate content problem.  The PageRank for the www.telikin.com/index.php page is not contributing towards the PageRank for your www.telikin.com page.  You should 301 redirect www.telikin.com/index and www.telikin.com/index.php to www.telikin.com.  Personally, I don't know how to write the actual redirect, but make sure when you do it that your home page works as you could potentially create an infinite redirect when messing with your site's index page.

The trailing slashes don't matter, meaning Google knows www.telikin.com/index.php/ is the same page as www.telikin.com/index.php, so you don't have to concern yourself with that.