The BBC’s websites are now back to normal, four days after being taken down by an effective DDoS attack on New Year’s Eve.
The BBC mitigated the attack within a few hours by moving its main website onto the Akamai content delivery network, which restored access to its millions of users. However, during this mitigation period, some of the BBC’s other websites – which were still hosted at the BBC – remained mostly unreachable.
The BBC’s DDoS mitigation was only temporary, and last night it moved its main website off Akamai, back onto a netblock owned by the BBC. This move resulted in another short outage on 4th January, followed by several hours of slightly slower response times within the UK. By the 5th January, the response times had settled down to be almost comparable with when it was using Akamai.
However, as expected, response times from other countries are no longer as fast as they were when the BBC’s main website was hosted on the Akamai CDN. Response times from the US are notably slower, but currently no worse than they were before the DDoS attacks on New Year’s Eve.
During the period in which the BBC’s main website was hosted on the Akamai CDN, its legacy News website at news.bbc.co.uk remained hosted at the BBC. This was mostly unavailable during this period, with most client connection attempts being reset.
This site’s availability was restored to normal at the same time that the main BBC website moved off Akamai. This suggests that the connection resets were a deliberate attempt to mitigate basic DDoS attacks, rather than as a direct side effect of a sustained DDoS attack. However, this approach was not ideal – while some browsers (such as Chrome) would automatically retry the connection attempt (often successfully), other browsers would give up at the first failure.