Nepal government’s main server has faced cyberattacks leading to disruptions of hundreds of government websites across the country on Monday.

According to the National Information Technology Centre, the websites have gone offline due to distributed denial of service (DDoS) attacks which are a subclass of denial of service (DoS) attacks. A DDoS attack involves multiple connected online devices, collectively known as a botnet, which are used to overwhelm a target website with fake traffic.

“Government sites have received massive traffic since Sunday despite our firewall blocking them. Some websites are operational on desktops while others on smartphones,” said Prabin Chauhan, spokesperson of the centre. “This is a DDS attack. We are blocking unnatural IP addresses. Websites will be operational slowly,” said Chauhan.

Spokesperson Chauhan says it is difficult to prevent such attacks as licenses of security tools used for cyber security and websites are yet to be renewed.

In January last year, similar cyberattacks resulted in disruptions of hundreds of government websites across the country and also hit international travel due to the shutdown of the immigration server.