Updated Domain hosts Point DNS has been hammered with a high intensity DDoS attack on Friday, knocking servers out for hours.

The size of the attack and techniques used - much less who might be behind the attack - remains unclear. Several Reg readers got in touch to notify us about the issue and the company confirmed the attack online.

"We're experiencing a DDoS attack on all DNS servers we are working hard mitigate the attack," Point DNS said in a update to its Twitter profile. "We're still working through a massive DDoS. We're adding more nameservers and working with our network providers," it added.

The firm, whose services are used by more than 220,000 domains, was badly affected by the attack. This had a knock-on effect on firms who used its services - while websites were up and running as normal attempts to reach them by typing in a name to a browser would not resolve as normal.

The snafu also means email won't be delivered as normal to affected sites, with early indications suggesting clients clustered in Asia and Europe were worst affected.

Security specialists Incapsula spotted a similar attack, which peaked at 25 million packets per second. It reported seeing floods of non-spoofed IP data coming from two DDoS protection services as the cause of the outage.

"DNS flood have been around for a while but now the modern high-capacity servers take the attack to a new level," Incapsula product evangelist Igal Zeifman told El Reg in a statement.

"Unlike amplification attacks, that could be easily spotted and filtered on-edge, DNS flood queries can't be dismissed before they could be allowed to be processed by the server. With powerful botnet machines pumping millions of malicious request each second, and aiming them directly and the most vulnerable server resources (eg CPU), the old threat is now making a comeback in a very dangerous manner."

Copper.io provides a suite of tools in the modern app stack to over 65,000 developers. PointDNS is one of its products.

Ed Byrne of copper.io explained that the attack began in the early hours of Friday morning (US west coast time) and had the knock-on effect of making customer queries unresponsive for around four hours, until it was able to get a secondary network up and running.

Byrne told us on Friday: "DDoS attacks - as you know I'm sure - are not uncommon - this one was just an order of magnitude larger than anything we had seen before. The exact amount of traffic I don't know yet - we've multiple network providers - and the spread of IPs was in the high thousands.

"It originated from China. The attack is still ongoing but subsiding and we've mitigated the impact to our customers," he added. ®