ORDER
This is a frivolous appeal. Peter Prostya-kov and Masco Corporation have been suing each other since them business relationship fell apart more than 20 years ago, when Masco discharged Prostyakov. Their dispute precipitated two arbitrations for claims for breach of contract. See Prostyakov v. Masco Corp., 513 F.3d 716 (7th Cir. 2008); see also Masco Corp. v. Prostyakov (Masco Corp. II), 593 Fed.Appx. 570 (7th Cir. 2015); Masco Corp. v. Prostyakov (Masco Corp. I), 558 Fed.Appx. 685 (7th Cir. 2014). We have previously affirmed the district court’s decisions to confirm the arbitration awards, see Prostyakov, supra, 513 F.3d at 727; Masco Corp. I, supra, 558 Fed.Appx. at 688, and to sanction Prostyakov with a fíne of $25,500 for filing needless motions, see Masco Corp. II, supra, 593 Fed.Appx. at 570-71.
Undeterred, Prostyakov returned to the district court. Invoking Fed. R. Crv. P. 60(b)(3); which allows district courts to reopen cases based on fraud, he asked the court to overturn its prior judgments. He observes that the district court’s original decision confirming the first arbitration award included the sentence “Prostyakov was discharged for alleged theft.” Prostya-kov contends that Masco fabricated that *525allegation. But Prostyakov was aware of that allegation throughout this entire litigation, so it is not new. He had an opportunity to challenge the allegation during the arbitration, in the district court before it confirmed the arbitration awards, and on direct appeal from that confirmation. He may not do so, however, through a collateral attack under Rule 60(b)(3). “Otherwise ‘fraud on the court’ would become an open sesame to collateral attacks, unlimited as to the time within which they can be made by virtue of the express provision in Rule 60(b) on this matter, on civil judgments.” Oxxford Clothes XX, Inc. v. Expeditors Int’l of Wash., Inc., 127 F.3d 574, 578 (7th Cir. 1997).
Because this appeal is frivolous, we give Prostyakov 14 days to show cause why we should not impose a sanction of $5,000.
AFFIRMED.