What is claimed is: 

## CLAIMS 

1. A method for dynamically learning and using foreign mobility management node information for telecommunications network security screening, the method comprising: 

operating a telecommunications network routing node in a learn mode in which traffic from foreign mobility management nodes is received and identities of the foreign mobility management nodes are learned and used to populate a security database maintained by the telecommunications network routing node; 

operating the telecommunications network routing node in a test mode to dynamically learn foreign mobility management node security status and maintaining the security status for the foreign mobility management nodes in the security database; and 

operating the telecommunications network routing node in an active mode to filter traffic from the foreign mobility management nodes using the dynamically learned node identities and security statuses. 

2 . The method of claim 1 wherein operating the telecommunications network routing node in a learn mode includes querying a home location register (HLR) or home subscriber server (HSS) to identify an old mobility management node and an age of location parameter and populating the security database with an entry corresponding to the old mobility management node and the age of location parameter. 

3. The method of any preceding claim wherein operating the telecommunications network node in the learn mode includes performing validation testing for mobility management node identities extracted from received messages, updating validation pass and fail counts in the security database based on results of the validation testing, and updating the security statuses based on the validation pass and fail counts. 

4 . The method of any preceding claim wherein operating the telecommunications network routing node in the learn mode includes 

