This isnt something to discuss on the SURBL list, but it looks like you either have a dictionary attack going on.
I'm sorry. I should clarify on list (though I do appreciate the offer of off-list support)
All of these connections do not seem to proceed past the connection startup phase.
I am very used to dictionary attacks having hosted sites and DNS that bring ire from Spammers (formerly www.spamassassin.org and currently just DNS, an SURBL public nameserver, RelayRegistry.org, anti-SPAM How-To's, etc). This looks like a VERY large distributed Denial of Service attack.
The reason I posted here and I believe it is relevant because it might be against SURBL nameservers and I'm hoping to hear if others are seeing the same issue.
Regards, KAM