What's the best way to redirect a short domain name to a longer one without having duplicate content issues?

• I recently set up a shorter domain name that 301 redirects to my main site which has a much longer, keyword relevant dot.com domain name.

  Example: ShortName.com redirects to LongerDomainName.com

  I want to avoid duplicate content issues and therefore stop Google from listing the shorter domain. So, for the ShortName.com I've set up my robots.txt file like this?:

  User-agent: *
  Disallow: /

  Is this the proper way to do this?

Answer:

After looking at the (actual) domains you gave us, it appears that your ShortName.com is 301 redirecting to LongerDomainName.com as intended. Although this should prevent Google from surfacing that domain in search, it will likely show up if you do a site search (i.e., site:ShortName.com)

However, the current 301 redirects appear to be keeping it from showing anything but the home page. This should not be a problem really, with the redirects it's not going to be a duplicate site in Google's eyes anyway.

However, you should consider making the short domain go 404 — delete the home page temporarily, remove the redirect, then go to the Google Search Console for the short domain and remove the home page.

After it's been removed, then add the robots.txt block to keep the site from surfacing at all. After that, add the redirect back in.

In the future, prior to making a new domain like that live, you should put the robots.txt block in first to avoid this extra work, then add the redirect.