My blog has let make a long winded URL, I have (elsewhere) acquired therefore after several months a brief second URL and forwarded directly to the first. If the new input then is the old top and will possibly saved. Question: Does the bottom described problem for me / I must leave what change?
I read in a text of 2008: "Any content is only accessible under exactly a URL One of the main SEO principles, which is still disregarded the most." and "Of particular relevance is the problem, because normally not only a product with an incorrect URL is error at this point crawled and takes the index of the search engine, but mostly by the anchoring of the faulty URL schemes in CMS and all other products are duplicated and so in addition to the example 200.000 correct article URLs another 200,000 duplicates are indicated with the same content but different URL. This frequently encountered errors may lead to massive SEO problems and, in extreme cases the exclusion of the entire site from the Google index have the result. " (Source: Page 7 .pdf "Fundamentals-of-SEO" v Thomas Promny, freeware from the Web.)
The best answer
You write that you weiterleitest the page. Thus, there is then no duplicates. Users and crawlers are indeed forwarded immediately from Domain A to Domain B. Agent 301 redirect tells the search engine is that the content to be indexed are and sends the crawler directly to another page on the other side.
Why you lead actually to the new to the old domain? If the old one is so complicated it would not be more the old redirect to the new domain?
how you conduct because of the one to the other site in order? Generally you must make sure that the server to server code 301 reports back (moved permanentely).
I'm like damer think you should use the new short URL as the main domain.
Incidentally, no one is punished for "duplicate content" by Google. However, Google takes out the right at two sides of the same (or nearly the same) content to decide which of them to the search term entered, and then displays it preferably in the SERPs (Search Engine Result Pages) at relevant. Google wants the seeker show whenever possible the most appropriate site. When two equal sides, it happens again and again that Google today times the one, then the other side tomorrow preferred (= indicative). Punished but none of the two sides in the proper sense.
Beautiful Christmas greetings!