SIP NAT
If you have deployed FreeSWITCH behind a NAT Gateway, you need to configure the other side to allow SIP NAT Traversal
Here's a good article describing the problem of SIP and NAT traversal and how it is overcome.
Below is a list of different vendors with details about how to set up SIP NAT traversal.
Symmetric latching, or forced HNT, ensures that symmetric RTP/RTCP is used for a SIP endpoint. Symmetric RTP/RTCP means that the IP address and port pair used by an outbound RTP/RTCP flow is reused for the inbound flow. The IP address and port are learned when the initial RTP/RTCP flow is received by the Oracle® Enterprise Session Border Controller. The flow's source address and port are latched onto and used as the destination for the RTP/RTCP sourced by the other side of the call. The IP address and port in the c line and m line respectively in the SDP message are ignored.
If your network is configured with nested realms in order to separate signalling from media, make sure that the symmetric latching feature is enabled on the signaling realm.
