Method for realizing network address translation (NAT) traversal of voice over internet protocol (VoIP) based on kamailio

The invention relates to a method for realizing NAT (Network Address Translation) traversal of VoIP (Voice over Internet Protocol) based on Kamailio, which comprises the following steps of: when a user agent after registration and NAT needs to register, performing identity verification on registration information by Kamailio; enabling the registration information request of the telephone to trigger the Kamailio to send the registration information request to the IPPBX, enabling the IPPBX to automatically sends= an online telephone invitation to the Kamailio, and sending all invitation information sent from the IPPBX to a target user after being processed by a user address; calling: the user agent starts the calling, when a new call arrives and passes identity verification, the Kamailio forwards the new call to the IPPBX, if a callee is online, the IPPBX sends the call to the Kamailio, and the Kamailio searches an address and sends the address to a caller; and enabling a keep-alive mechanism of the user agent