The network layout it something like: FS and Ext 3 <- Local Net ->Inet Rtr(Static NAT) <== INET ==>Inet Rtr(Dynamic NAT)<- Local Net -> Ext 1 and Ext 2 where: The public IP of the Freeswitch box is static There are 2 sip profiles, one for the internal clients on 5060 and one for the NATd clients on 5070 with the external IP hard set and Freeswitch running with -nonat Ext 3 is on the same subnet as the FS server and is using sipinterface_1 to connect Ext 1 and Ext2 are on the same subnet on the remote side of the double nat and using sipinterfacec_2 I can call from Ext 1 to Ext 3 with no problem I can call from Ext 2 to Ext 3 with no problem When I try to call from Ext 1 to Ext 2 or Ext 2 to Ext 1, I get a 606 USER_NOT_REGISTERED show registrations seem to indicate that they are, and I can't find any difference in the call processing to the extensions that it works to, and those that it doesn't. Pastebin with registrations and failed call log is: http://pastebin.freeswitch.org/16705 Thanks in advance for any help...