There are a number of customers with open DNS relays on their networks. Some of these appear to be being exploited as part of a DDOS with, we think, spoofed source DNS lookups.
As this is undoubtedly causing problems for whoever is being attacked, as well as causing excessive broadband usage for affected customers, we are going to attempt to make a list of these relays so that the affected customers can be identified.
You may see DNS lookup attempts from one of our IPs in your firewall logs.