North Korea's dispute with the US over computer hacking took a new twist when the communist state lost Internet access for several hours - but how easy is it to shut down a country's computer connections?

The answer seems to be it depends on the country.

In terms of North Korea, cyber experts suggest it would be relatively straightforward to overwhelm its servers capacity and launch a distributed denial-of-service (DDoS) attack because the country only has 1,024 official Internet protocol addresses.

Caroline Baylon, cyber security expert at Chatham House, told ITV News DDoS attacks are "primitive but effective and very easy to wage because they require very little funds or technology."

In addition, North Korea's connections to the outside world are managed by Star Joint Ventures, the country’s state-run Internet provider, and almost all of them run through China Unicom, China’s state-owned telecommunications company.

Ms Baylon said any attack on Pyongyang would "probably" be possible without China as co-operation between the North Korean ally and the US is unlikely because of their frosty relationship.

China has dismissed any suggestion that it was involved in the outage as "irresponsible."

South Korea has not ruled out Pyongyang for a cyberattack on its nuclear power plant operator. Credit: Maurizio Gambarini/DPA/PA

US-based Dyn, a company that monitors Internet infrastructure, said the reason for the North Korean outage was not known but could range from technological glitches to a hacking attack.

North Korea is one of the least-connected nations in the world, and the effects of the Internet outage would have been minimal.

However, major websites, including those of the KCNA state news agency, the main Rodong Sinmun newspaper and the main external public relations company went down for hours.

US President Barack Obama had vowed on Friday to respond to the major Sony cyber attack, which he blamed on North Korea, "in a place and time and manner that we choose."

Ms Baylon said the US has been under pressure to respond to "provocative and contradictory" statements from North Korea.

She adds: "This could just be the start and it will be interesting to see how North Korea responds to this event over the next few weeks. This dispute is not going away and in fact is likely to escalate."

  • By Karen Rollins: Digital Producer, ITV News.