The internet around the world has been slowed down in what security experts are describing as the biggest cyber-attack of its kind in history.
A row between a spam-fighting group and hosting firm has sparked retaliation attacks affecting the wider internet.
It is having an impact on popular services like Netflix - and experts worry it could escalate to affect banking and email systems.
Five national cyber-police-forces are investigating the attacks.
Spamhaus, a group based in both London and Geneva, is a non-profit organisation that aims to help email providers filter out spam and other unwanted content.
To do this, the group maintains a number of blocklists - a database of servers known to be being used for malicious purposes.
Recently, Spamhaus blocked servers maintained by Cyberbunker, a Dutch web host that states it will host anything with the exception of child pornography or terrorism-related material.
Sven Olaf Kamphuis, who claims to be a spokesman for Cyberbunker, said, in a message, that Spamhaus was abusing its position, and should not be allowed to decide "what goes and does not go on the internet".
Spamhaus has alleged that Cyberbunker, in cooperation with "criminal gangs" from Eastern Europe and Russia, is behind the attack.
Cyberbunker has not responded to the BBC's request for comment.
'Immense job'
Steve Linford, chief executive for Spamhaus, told the BBC the scale of the attack was unprecedented.
"We've been under this cyber-attack for well over a week.
"But we're up - they haven't been able to knock us down. Our engineers are doing an immense job in keeping it up - this sort of attack would take down pretty much anything else."
Mr Linford told the BBC that the attack was being investigated by five different national cyber-police-forces around the world.
He claimed he was unable to disclose more details because the forces were concerned that they too may suffer attacks on their own infrastructure.
The attackers have used a tactic known as Distributed Denial of Service (DDoS), which floods the intended target with large amounts of traffic in an attempt to render it unreachable.
In this case, Spamhaus's Domain Name System (DNS) servers were targeted - the infrastructure that joins domain names, such as bbc.co.uk, the website's numerical internet protocol address.
Mr Linford said the attack's power would be strong enough to take down government internet infrastructure.
"If you aimed this at Downing Street they would be down instantly," he said. "They would be completely off the internet."
He added: "These attacks are peaking at 300 Gbps (gigabits per second).
"Normally when there are attacks against major banks, we're talking about 50 Gbps"
Clogged-up motorway
The knock-on effect is hurting internet services globally, said Prof Alan Woodward, a cybersecurity expert at the University of Surrey.
"If you imagine it as a motorway, attacks try and put enough traffic on there to clog up the on and off ramps," he told the BBC.
"With this attack, there's so much traffic it's clogging up the motorway itself."
Arbor Networks, a firm which specialises in protecting against DDoS attacks, also said it was the biggest such attack they had seen.
"The largest DDoS attack that we have witnessed prior to this was in 2010, which was 100 Gbps. Obviously the jump from 100 to 300 is pretty massive," said Dan Holden, the company's director of security research.
"There's certainly possibility for some collateral damage to other services along the way, depending on what that infrastructure looks like."
Spamhaus said it was able to cope as it has highly distributed infrastructure in a number of countries.
The group is supported by many of the world's largest internet companies who rely on it to filter unwanted material.
Mr Linford told the BBC that several companies, such as Google, had made their resources available to help "absorb all of this traffic".
The attacks typically happened in intermittent bursts of high activity.
"They are targeting every part of the internet infrastructure that they feel can be brought down," Mr Linford said.
"Spamhaus has more than 80 servers around the world. We've built the biggest DNS server around."

So, has anyone been feeling the brunt of this attack yet? So far my bank has been hit; it's near impossible to get into my account remotely. And then last night a few popular sites such as Youtube were getting incredibly slow intermittently. No idea what'll happen next.

THAT FUCKING EXPLAINS IT! Yesterday morning my bank's system was down. I don't know if it was from this, but it could be. Youtube was pretty slow for me later yesterday and internet in general was a bit slow. I was confused because my internet is really fast. I keep my computer clean to keep it running smooth and the router is really good.

Fuck. 300Gbps is no joke. The thought that it fucked up the whole internet is scary. Someone must be seriously pissed off. All I can say is I hope Anonymous doesn't result to this since that's their favorite method of taking down websites. I also can say I'm glad Google's involved. They have so much extra space that they often lend it out for large projects that need it. There's no doubt that them lending a helping hand can have a lot of give to the damage being done.

Dude, to tear down a system is one thing, but the whole internet? The thought that they're slowing it down is scary, and that just shows how delicate it really is, and it brings these ideas that many sci-fi related things bring up of the possibility to completely turn off a country's electricity to take them down. It's actually possible. It makes me shudder.

Who's your bank? I go through US Bank, but BOA and Citi may also be affected right now.

Here's the thing: they aren't going to take the entire internet offline. My theory is they are looking for something. A specific vulnerability; I don't know if you remember, but last year a few utility systems were taken offline by a virus in an American city. I'm thinking that they're trying to find a specific public infrastructure that they can do significant damage to; and when they find it, they're going to start holding entire governments at gunpoint.

>>3 My bank's online lately, but they were off for a moment. I don't think that my bank is really important enough for them to be taking hostage or anything. I can say this though. Between this and the shit with North Korea, America's fucked themselves over.

If this keeps up, this means no interwebz.

And no interwebz means a majority of the human population dying.

And a majority of the human population dying would include me.

I CAN'T LIVE WITHOUT INTERWEBZ!

same here but its better than yesterday for me

I don't get it, what did they attack again ?
Was it Spamhaus or ICANN ?

Sounds like Spamhaus is the primary target, but as mentioned earlier, other types of servers (banks and the Netflix streaming service in particular) have been slowed by either the aftermath of these attacks or might be targeted without their knowing.

Oh I re-read it now i get it.
Google is just awesome you know, they gave their own servers to redirect traffic.

But don't worry only websites that require spamhaus to work will be affected all others will be good.

So no, this doesn't mean no "interwebz" everything just slowed down because google provided their own servers to spamhaus, since a lot of webistes need google to operate they have been slowed down too, for exemple nothing happened here.

A hosting company of pedophiles, and a spam block company of guys living in their parents basements aren't going to slow down the internet. ._.

>>10
The Internet already was slowed down, so your post is irreverent.

>>10 Well I don't think that some guys living in their parents basement could create such a massive DDoS with the power of 300 Gb/s so we can agree that they are not just "some guys".

To do that you'll need lots of computers.. and I mean lots, not just the right software.

But still, the internet is a huge thing. By the looks of this story, it's two different companies going at it, I'd believe it'd have it all slowed down if it was may 20 different companies and groups going at it, but this is just two out of billions of data and such on the internet.

>>13 read this >>9

>>13 Do you know how the internet works?

true . internet its slow but at least we can use it '^' we should be happy because its werry usefull thing

>>13 You just gave me a huge headache...

I wonder if this would end up big.