The number of TCP connections per minute from the source IP address 10.16.23.54 exceeded the configured limit. Forefront TMG will not allow the creation of new TCP connections from this source IP address during a system-defined time period. By default, this time period is 1 min.
This event indicates that this IP address probably belongs to a host that is infected by a worm and attempts to propagate the worm to other vulnerable hosts.
See the product documentation for more information about Forefront TMG flood mitigation.