We are currently dealing with an exponential increase in SPAM throughout the network, mostly originating from Asia. At this point the overall utilization of the network is at 61% (daily peak) and we are looking to isolate the cause of the behavior. It appears to either be a new worm or the restart of the spambot network we noted earlier this year.
Of note, Rogers Canada has started blocking port 25 traffic on the major part of their residential network. ExchangeDefender is not supposed to be implemented on dynamic / residential services but if you have done so and are experiencing issues, please be advised that your port 25 may be blocked.