Jack- This is exactly what we're seeing. The Akamai server starts a retransmission flood aimed at a specific address randomly. We're seeing thousands of retransmissions of the same packet over and over again, same sequence/ack numbers, all 1460 bytes. In the last capture I have, it was all JPEG data, although we weren't capturing entire packets. There is a slight difference in the capture payloads, two bytes each time. I had another dial-up provider contact me off list, and he's seeing the same thing. I'm wondering if this is actually more widespread, but only dial-up providers are really seeing the effects since a 3-5Mbps burst is most noticeable for us on our smaller upstream links. // On 1/21/2011 8:45 AM, Jack Bates wrote:
I have a customer reporting the same thing. The traffic flood goes to offline modem bank IPs. So far, Akamai hasn't actually grasped what the problem is and says everything is fine. :(
Luckily, most of the traffic (not all) is coming from my local cluster, so it's easier to monitor what's going on. Packet captures have shown the same packet being sent over and over, usually over 1400 bytes in size. Different floods may have different packets, but within a flood it's identical. I wouldn't think you'd have data prior to the 3-way, so I'm curious how the 3-way is being completed for the data to be sent.
Jack
On 1/20/2011 4:46 PM, Tom Beecher wrote:
I've received a couple of responses off list, and am now in touch with Akamai directly.
I appreciate everyone's assistance.
On 1/20/2011 4:04 PM, Tom Beecher wrote:
I'm looking for an Akamai contact to try and address a strange situation.
We have multiple sites across the country that aggregate 56k dialup customers. Different sites are randomly experiencing inbound traffic spikes that are overwhelming the uplinks to our carriers, causing DoS situations. These spikes far exceed the bandwidth that could possibly be used by the number of dialup customers connected. We've been able to trace the source of the traffic to Akamai boxes, but so far have been unable to reach anyone at Akamai to discuss the situation. We're attempting to get payload information, but the traffic volume is making it slow going setting up packet captures at these sites remotely.
Thanks in advance,
Tom
-- Thomas Beecher II Senior Network Administrator LocalNet Corp. CoreComm Internet Services tbeecher at localnet.com