中文摘要：

根据对称型NAT的映射特点,提出了一种改进后的穿越对称型NAT方案,并在具有对称型NAT的应用场景的相关实验测试中取得了较好的实验结果,达到了预期的目标。新方案具有STUN方式无需更改NAT设备、协议相对简单等优点,能很好地满足企业既能节约IP地址又具有较高安全性的NAT需求。

英文摘要：

According to the feature of the symmetric NAT, an improved symmetric NAT traversal approach was proposed in this paper. In the application scene with symmetric NAT, good results were gotten in related experiments and tests and the expected goal was achieved. The proposed approach has the advantages of STUN protocol, such as simple protocol and no modification of existing equipment. It well meets the demands of enterprises on both saving IP address and enhancing security of NAT.