This has been a topic of user feedback for oil filters purchased off of EBAY and Amazon. I knew enough not to order a filter that didn't come in the original packaging, but even that is not enough to ensure authenticity. I got a fake Mercedes/Mann filter in the mail today. I have purchased both genuine Mann filters as well as the Mercedes re-branded filters from a dealership. Today I received this in the mail and it is fake:
https://www.ebay.com/itm/Engine-Oil-...S/174145635781
Compare it to a genuine Mann filter (yes, I have ordered from THIS merchant and it is valid):

The first and BEST clue that the former is NOT GENUINE is that the 2 black "ink" marks denoting how far up the plastic shaft to place the filter are absent. Next you'll notice that the adhesive used at either end of the filter is a darker glue than that of the genuine filter. For ***** & giggles I've ordered a Hengst fleece filter to have that to compare against as well as another GENUINE Mann filter so I can sit all 3 side by side and take pictures for comparison purposes. Once I do i'll post that here.