NewsletterCyber BulletinIran’s Internet Blackout Among Most Severe Ever, Experts SayCustom blocking tools have replaced brute-force shutdowns.FacebookXLinkedInEmailLinkGiftExpandView of the skyline in Tehran, Iran.Photographer: Abbas Kowsari/Bloomberg NewsFacebookXLinkedInEmailLinkGiftGift this articleContact us:Provide news feedback or report an errorConfidential tip?Send a tip to our reportersSite feedback:Take our SurveyNew WindowFacebookXLinkedInEmailLinkGiftBy Patrick Howell O'NeillJanuary 21, 2026 at 6:49 PM UTCBookmarkSaveLock This article is for subscribers only.