An 'unprecedented' cyber attack is slowing down the internet after a feud erupted between spam-fighting group Spamhaus and hosting firm Cyberbunker over a server blocklist database.

According to the BBC, Spamhaus claimed it had been under attack from Cyberbunker for over a week and the knock-on effect could be reaching widely used services such as Netflix, as its Domain Name System (DNS) servers were targeted and struggled to cope with the pressure. Google is understood to have provided resources to try and ease the pressure.

DNS servers are the internet infrastructure which joins domain names, comparable to an online phonebook. The cyber attack involves directing large amounts of traffic towards the server which clogs pathways, in what is called a Distributed Denial of Service (DDoS).

The chief executive of Spamhaus, Steve Linford, told the BBC: "If you aimed this at Downing Street they would be down instantly. They would be completely off the internet. Normally when there are attacks against major banks we're talking about 50 gb/s (gigabits per second). These attacks are peaking at 300 gb/s."

The row broke out after non-profit organisation Spamhaus blocked servers maintained by Dutch web host cyber bunker, which hosts any content except child pornography or terrorism material. Spamhaus helps email providers filter spam and unwanted content and claimed Cyberbynker was conducting the attack in cooperation with "criminal gangs" from Russia and Eastern Europe. Five national cyber police forces are reported to be investigating the attack.

Phyllis Schneck, vice president & chief technology officer, Global Public Sector for McAfee, commented in response to the news: "Denial of Service (DOS), and Distributed Denial of Service (DDOS) attacks are not new, and do not demand significant technical expertise to initiate. However their impact as we have recently witnessed can be significant. Due to the connected nature of digital citizens, a dispute between key parties will impact everyone from consumers to SMB to large enterprises."

Spamhaus insisted its servers were holding out under the attack and would not be brought down.

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