Backlinks from subdomain, can it hurt ranking?

[MMAffiliate]

I just started doing an SEO audit and noticed I have 40,000 some odd back links from an OLD version of our site that has been moved to a subdomain. The back links are for articles that already exist on our main site. I don't think Google is picking it up as duplicate content because that site isn't being crawled anymore. Could this hurt us SEO wise? I plan on removing the site, but how long after it's been removed should those back links disappear?

[Carson-Ward]

So there were no external links pointing to the subdomain admin.site.com ? If that's the case you could probably just noindex/nofollow the thing or let it 404. You could write an .htaccess rule to rewrite the domain name, but it's actually probably not worth it now that I think about it. The exception, of course, is if the subdomain had external links pointed to it.

[MMAffiliate]

Hi there,

Thanks for your reply. I'm not sure how feasible it is to redirect all of those urls. I know I could use regex but I just terminated the server that admin.site.com lived on so I can't access a robots.txt file anymore. Could I simply do a generic redirect admin.site.com -> site.com?

The subdomain was the same site and domain.

Thanks.

[Carson-Ward]

Okay, so the situation here is a little unclear, but the solution should be pretty straightforward.

If the admin.site.com was different from the original site domain, simply noindex/nofollow all of the pages on that domain. I recommend this over a robots.txt rule because it will actually remove them from the index. You can add a disallow all rule in robots.txt later once the site is completely noindexed.

If the admin.site.com was the same domain, I'd recommend redirecting all of those pages to the new URLs again and then launching a noindex/nofollow version blocked with robots.txt, though I'm not sure why it needs to exist for reference. If the subdomain was different from the old site you could also probably just noindex/nofollow all of it without the redirect. It's not best practice, but it's not that big a deal.

Hope this helps to answer.

[DmitriiK]

If you took website down, you don't have to really do anything. Go to search console, do fetch as google on old admin subdomain, so google understands that it's not there anymore, and then just wait. Google will take those backlinks down.

[MMAffiliate]

The other thing I should note is that these site links do not show in Google when searching for the topic. I'm only seeing reported back links because the admin.site.com subdomain was blocked from Google crawling it for search results. Not sure if that makes a difference.

[MMAffiliate]

It says I can only demote 100 links, I need to demote upwards of 40,000 since the admin.site.com basically mirrored the actual site.

Now I'm a little confused.

I took the old site down, so I can use a robots.txt file there anymore.

So how can I disallow the entire admin subdomain and stop reporting back links?

[DmitriiK]

I see. Read my response below and just use meta robots. it will help you out.

If you want to deindex those backlinks, you also can look into Google Search Console's demoting tool, but i don't think it's necessary.

https://support.google.com/webmasters/answer/47334

[DmitriiK]

Don't do that, disallow in robots.txt will NOT resolve indexing issue! What you need to use is meta robots. Noindex, nofollow. Watch this WBF on this subject:

https://moz.com/blog/controlling-search-engine-crawlers-for-better-indexation-and-rankings-whiteboard-friday

[MMAffiliate]

Thanks

[MMAffiliate]

Hi there. Thanks for your response.

The pages exist on the new site, but the subdomain should have never been indexed. I noticed the back links in Google Console initially then confirmed with SEO Power Suite.

Basically we had site.com, then created a brand new site and migrated content over to newsite.com with 301 redirects from the old site. Then we wanted to keep the old site up for reference so we put it at admin.site.com. That is where all the 40,000 back links were coming from, admin.site.com, the old site.

There is no reason for us to redirect admin.site.com since the original articles were properly redirected. I guess however some how when the old site was taken down, Google must have indexed it still at the subdomain and counted those as backlinks.

[Toddfoster]

Just make sure you add a robots.txt to the subdomain with

User-agent: *
Disallow: /

Or if the old site is not needed anymore, redirect the subdomain to your main domain and remove the site.

[DmitriiK]

Hi there.

So, all the pages, from which those backlinks are coming from are non-existent anymore? have they been redirected? do they return 404s? Also, how did you find them? in Google Search Console or another tool?

So, if you found it in Google Search Console, and the original pages indeed have been removed and properly redirected, then it's just time delay by GSC. Otherwise (if those pages are crawlable), you should fix it.

Hope this makes sense.