I'd stick with one version, either just domain-name or domain-name/index.php, and add <link rel="canonical" href=" ... "> in the <head> ... </head>, so that the page is canonicalized. Otherwise, search engines sometimes look for both versions of the page (especially if there are links to both versions).
Version was not a well-chosen word, but both domain-name and domain-name/index.html used to turn up on my Google WMT / Yahoo Site Explorer as separate URIs, each with incoming links, before canonicalization. Let's put it this way: even if makes no difference practically, surely there is no harm in making one URI canonical, just to be on the safe side.
even if makes no difference practically, surely there is no harm in making one URI canonical, just to be on the safe side.
Granted, you can do that but the question is if that somehow might harm SERP
and from my own experiences it doesn't. Better yet Algo grabs both versions of
Code and places in SERP sometimes 4 - 6 pages apart. What's wrong with that?
For canonicalization, the file extension, such as php or html, doesn't matter.
It is merely a question of pointing out to search engines which of the multiple URIs pointing to the same file ought to be seen as canonical. Let's say there is a page called index.extension, which is what someone sees when he or she types in domain-name or domain-name/index.extension. As mentioned earlier, search engines sometimes treat domain-name and domain-name/index.extension as two separate URIs (despite the fact that they point to the same file), as evidenced in Google WMT and Yahoo! Site Explorer backlinks data.
By, for example, adding <link rel="canonical" href="domain-name"> in index.extension file, which makes domain-name the canonical URI, then that combines incoming links to both domain-name and domain-name/index.extension for domain-name, and it also reduces the possibility of duplicate results appearing in SERPs.
Arguably, canonicalization is much more important for sites that use session IDs or parameters on their pages heavily, but I'd maintain that there's no harm in doing it for the home page.