Duplicate content issues from mirror subdomain : facebook.domianname.com

[b2bmarketer]

Hey Guys, 
Need your suggestions.
I have got a website that has duplicate content issue. 
a sub-domain called facebook.asherstrategies .com comes from no where and is getting indexed. 
Website Link : asherstrategies .com
subdomain link: facebook.asherstrategies .com

This sub domain is actually a mirror of the website and  i have no idea how is is created.
trying to resolve the issue but could not find the clue.

[Andy.Drinkwater]

Hi,

It sounds like a config issue either with the host, .htaccess or could even be something within the site settings itself. What is it that powers the site? Drupal, Wordpress etc?

Cheers,

Andy

[b2bmarketer]

@Andy Drinkwater I checked for htacess, but could not find any clue, the website is in flat php.

[MonicaOConnor]

Sounds like someone doing off page optimization created a subdomain for the purposes of increasing domain authority by posting a ridiculous amount of social posts through a subdomain. This is extremely black hat and that is why it is on a subdomain, to protect your root. I have come across this issue on blackhatworld.com.

I recommend you shut down the subdomain immediately and ask whoever is handling your off page optimization what in the world they were doing. I doubt it is an older subdomain because this is a fairly recent practice. I would recommend getting rid of it fairly quickly and making sure that there are not many links between the sub and the root domain.

[CraigBradford]

It looks like there is a canonical tag on the Facebook version of the site but it's still not a great idea. Unless there is a really good reason I'd remove the site.

Craig