Make sure you have a good reason for the check. It will only be accepted to counter vandalism or disruption to Wikimedia wikis. Valid reasons include needing a block of the underlying IP or IP range, disruptive sockpuppetry, vote-stacking, and similar disruption where the technical evidence from running a check would prevent or reduce further disruption.
Be specific in your reasons. Ambiguous or insufficient reasons will cause delays. Explain the disruption and why you believe the accounts are related, ideally using diff links or other evidence.
Make sure there are no local checkusers or policies.
Reason(s): Bonjour. Il y a actuellement une vague de créations de pages sur fr.wikisource.org, venant de multiples nouveaux contributeurs, qui ont la même façon d'agir. Nous soupçonnons qu'il s'agit de la même personne, sans pouvoir en être sûrs, n'ayant pas de check-user local. Ces pages créées sont parfois des doublons de pages, parfois de nouvelles pages non sourcées, ce qui nous gêne car nous voulons savoir d'où viennent les textes en question.
Hello. On fr.wikisource.org, there is currently a wave of creation of new pages, from new contributors, and we suspect these people are a same person, but we can not prove it, because we do not have local check-users. These new pages are pages we already have, are pages without references, which is completely annoying because we want to know where these texts come from. Can you help us please ? Consulnico (talk) 17:48, 28 February 2017 (UTC)
Addedum : THIS REQUEST IS SUPER URGENT. Currently, someone is creating an account every thirty minutes, then creates a page without references, and then disappears definitely. Can you help us ? Can you discover the IP behind these creations ans, I think, block it from creating accounts, so that we can speak with that person. --Consulnico (talk) 18:34, 28 February 2017 (UTC)
Doing... Hard to say. I have the feeling these are multiple groups, but can't prove it yet. Could use help from someone else... Trijnsteltalk 19:16, 28 February 2017 (UTC)
Thank you for your help. I will edit the request if I see other accounts created with the same unusual scheme of contributions. --Consulnico (talk) 19:24, 28 February 2017 (UTC)
Looking into the edits I can see different users with different UA editing from the same ip. I assume they are classmates or similar. In some cases they share UA and ip, it is not rare when there is a shared public machine. IMHO MP. --Melos (talk) 20:07, 28 February 2017 (UTC)
Thank you for your time. We will investigate this. Two of the people I contacted have answered my questions, I hope your hypothesis is true. If we need further information, I will come back here. Thanks again ! --Consulnico (talk) 20:14, 28 February 2017 (UTC)
Reason(s): I have no doubt in my mind that user1 & user2 are two distinct users. Still, inline with discussion link, I have approached here for sockpuppet test.--Muzammil (talk) 16:29, 20 March 2017 (UTC)