IP ranges and matching WHOIS

[CareerBliss]

I have a client who owns two large websites and they sit on the same IP Range: XXX.XX.11.124 and XXX.XX.11.126. Obviously the X's match. Furthermore the whois in the same.

Website A is really old and has millions of pages, but has some unintentional but spammy subdomains that are duplicate content.... we are talking thousands. At this point addressing those subdomains is not an option. Website A also links to millions of times to Website B, but those links are either nofollowed or in javascript.

Website A has a ton of duplicate content through job feeds.

Now Website B is about 4-5 years old and has a great link graph but has been hit hard by Panda in which we recovered only to dive again. My question is, Website B is very close to having near perfect onpage SEO, hierarchy, etc. Could website A be effecting it in anyway?

If we assume that Website A is impacting B, what is the safest solution.... change servers and IP addresses? Change host entirely? Do I need to worry about whois?

Thank you!

[tjkirgin]

If You can't address them can you create a sitemap or robot that doesn't count them?

https://support.google.com/webmasters/bin/answer.py?hl=en&answer=156449

[AlanBleiweiss]

The question is this - why would you want to keep Site A given the current insurmountable challenge you describe?

Do you still hope there's some value in it being kept alive?

Do you still hope there's some SEO value or that the site will or does continue to bring some traffic you believe to be valuable?

Because (and this is just my opinion) if you are convinced you cannot or will not (for whatever reason) work to clean the mess up, you'd be better off completely killing off Site A.

If you don't even if you migrate site B to a different server, the links still exist. The footprint remains.

[CareerBliss]

Honestly.. Site A is a Cash Cow that does not need SEO. I would love to clean it up, but there are external forces preventing that at the moment. These forces are not technical.

Site B is in the same industry as A, but with a different model and user. Both sites are pertient.

Let me simplify this question....

1.Can duplicate content effect more than just the root domain and spread across to other websites on the same IP range? and WHOIS?

2. Moreover does any SEO need to worry about what their clients are doing on sites that are out of their control (assuming no blackhat techniques)?

[AlanBleiweiss]

If Site A is a cash cow that does not need SEO, then I would block the entire site from search engines via robots.txt file.  Even on separate hosts, all the links pointing to Site B are a big negative due to the sheer volume, given that there's likely a "bad rap" label associated with SEO on site A.

Duplicate content does not need a "same server" relationship to be a big problem either.  All duplicate content is a problem regardless of location.

If a client I represent is doing things that I believe are impeding their success, I personally believe it's important to communicate my concern. However, if they choose to ignore that communication, that's their right to do so.

[Cyrus-Shepard]

I think what your asking, at a deeper level, if the really crappy SEO on site A can effect site B, through some form of administrative relationship. Is this correct? If there is a lot of questionable linking between the sites, you can see some negative effects. (if there is no linking relationship between the sites, then the answer is almost always no)

I agree with Alan completely that changing servers, IP address and all that doesn't effect the issue that those links still point to your website. Changing the host or other administrative associations of any of these sites likely would have zero impact on any penalties.

First, you want to determine if site A really is the problem. Is it Panda? Is it Penguin? Make sure to match up the dates of your traffic fluctuation with historical algorythm changes. http://www.seomoz.org/google-algorithm-change

We seen a lot of site-wide cross linking, with over-optimized anchor text, as a key root of a lot of recent Penguin penalties.

All of these penalties have a lot of factors that could be the cause, so I'd make sure to look everywhere, including the links between the sites.