Security News > 2021 > October > South Korean telco KT suffers nationwide outage after routing error
The second-largest telecommunications provider in South Korea, KT Corporation, has suffered a nationwide outage today, leaving all its 16.5 million customers without internet connectivity and telephony services for about 40 minutes.
While the scenario of a DDoS attack was communicated as the most likely cause of the problem initially, the firm later explained that it was a routing error that took its services down.
Faulty routing configurations can be catastrophic, as we saw in a recent BGP routing issue that caused significant downtime for Facebook, Instagram, and WhatsApp.
BGP routing errors prevent data packets from reaching intended IP addresses and servers, causing a service disruption even though the services themselves are still up and running.
The short outage on KT caused a sudden overload on Korea's two other major telcos, SK Telecom and LG Uplus, whose users experienced service interruptions and hiccups as a result.
The last time KT's customers suffered from a major outage was in 2018, when a fire broke at its Ahyeon branch in Seoul, disrupting the services in the South Korean capital for days and forcing the firm to reimburse customer subscriptions.