Hi, Got a problem with a handset that doesn't seem to be registering on our Freeswitch server. The diagnostics from a member of Cisco support said... "At packet 422 we see the phone "0_4147057716@192.168.40.26" send a registration request to 5.9.36.113:5060 from 175.159.77.82:32060 - We do not see a reply to this from the SIP provider. We responses to requests from 0_359240637@192.168.40.26 <mailto:0_359240637@192.168.40.26> with source port 5060, which suggests to me that the SIP provider is not replying to the high UDP port requests. As the MX is a NAT device, subsequent SIP requests will always have a high UDP port." I'm not sure where we might configure acceptable ranges of SIP source or if it's something else. Thanks for any suggestions... Alex