AT&T blocking individual IP addresses

As of about an hour ago AT&T appear to have started blocking access to a few
of our IP addresses. This is being done at a /32 level, and the IP addresses
above and below are still allowed through.

Has anyone seen them do this before, or know who I need to contact to get it
fixed? AT&T won't talk to me as I'm not a customer...

Traceroute to the blocked IPs from AT&T all end at :
  5 ( [MPLS: Labels 20559/17406 Exp 0] 116
msec 20 msec 20 msec
  6 ( [MPLS: Labels 20527/17406 Exp 0] 24
msec 20 msec 20 msec
  7 ( [MPLS: Labels 0/17406 Exp 0] 24 msec
20 msec 20 msec
  8 ( [MPLS: Label 16623 Exp 0] 24 msec
20 msec 20 msec
  9 ( 20 msec 20 msec 20 msec
10 [AS 7018] 24 msec 20 msec 24 msec
11 [AS 7018] !A * *

Traceroute to the neighboring IP addresses don't go anywhere near the above
path, so it's apparently a blackhole of sorts.


Are they bots or C&C servers, or open DNS recursors?

They are (authenticated-required) proxy servers with 10's of thousands of
users behind them, so it's possible that they were seeing some bot-like
traffic from them, although the volume would have been tiny compared to the
volume of legitimate traffic.


So, if, say, AT&T customers are getting zorched from traffic behind those proxies, then blocking them would make sense, no?


Do you have visibility into the traffic into/out of those proxies, in order to determine if there's DDoS or spam or other undesirable traffic emanating from them?

So, wait, are they your addresses or not?

They are our non-AT&T addresses, and AT&T was blocking access to them from
their network, so any of our customers on AT&T were unable to access our

AT&T has now resolved the problem, claiming that it was a "provisioning