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Hi All, I'm facing a small yet big problem on one of my sites that I'll try to explain: I have a site with thousands of URL's, all with an odd link structure, like index.php/modules?=name=Video , etc I want to build a proper link structure and for that I'll have to replace that links. My question is: 1. Will I have any relevant SEO problem to do 301 redirects from the old links to the new?
2. Should I do it all at the same time or do it by parts?
3. What options do I have to avoid give not found errors / redirects for the old links? Thanks for the help.

Hi all, I'm managing a website that uses a redirect to show different languages to the users. I mean when a user access the site from any country it sees the full domain but when it access it from Italy, France or Germany it goes to domain.com/lang=FR or IT. I see that other sites use a technique to redirect to it.domain.com or fr.domain.com but I have doubts about which one is better. We do an aggressive link building strategy and we have a lot of links to the root domain across the various languages. Is it better to do the link building to the it.domain.com and fr.domain.com, depending on the language source of the link instead of the root? I'm seeing that some of our competitors are doing this but I'm afraid is going to spread the link juice across many subdomains and lose power to the root. Thanks in advance