Hi, Based on the latest discussions about inefficiency if the former contact matching alg, in the context of NAT traversal, I just committed into USRLOC support for configurable multi-algorithm for contact matching. For what algorithm are available, their description and how to select them, please refer to the online docs: http://www.openser.org/docs/modules/1.1.x/usrloc.html#CONTACT-MATCHING-ALGS I hope it will solve most of the problems... ;) regards, bogdan